Merge pull request #114 from davidgiven/fixing1

Add support for measuring signal line voltages.
Detect voltage levels *correctly*.
2025-10-24 11:11:02 -07:00 · 2019-12-11 00:28:13 +01:00 · 2019-12-11 00:05:34 +01:00 · 2019-12-10 22:36:18 +01:00 · 2019-11-29 22:02:44 +01:00 · 2019-11-29 18:49:22 +01:00
50 changed files with 7147 additions and 1979 deletions
--- a/.appveyor.yml
+++ b/.appveyor.yml
@@ -15,7 +15,7 @@ install:

 build_script:
  - make
-  - zip -9 fluxengine.zip fluxengine.exe brother120tool.exe
+  - zip -9 fluxengine.zip fluxengine.exe brother120tool.exe FluxEngine.cydsn/CortexM3/ARM_GCC_541/Release/FluxEngine.hex

 artifacts:
  - path: fluxengine.zip
--- a/FluxEngine.cydsn/CortexM3/ARM_GCC_541/Release/FluxEngine.hex
+++ b/FluxEngine.cydsn/CortexM3/ARM_GCC_541/Release/FluxEngine.hex
--- a/FluxEngine.cydsn/FIFOout/API/c.c
+++ b/FluxEngine.cydsn/FIFOout/API/c.c
@@ -0,0 +1,29 @@
+#include "cyfitter_cfg.h"
+#include "cydevice_trm.h"
+#include "cyfitter.h"
+#include "`$INSTANCE_NAME`_h.h"
+
+void `$INSTANCE_NAME`_Start()
+{
+   `$INSTANCE_NAME`_Init();
+}    
+
+void `$INSTANCE_NAME`_Stop()
+{
+    `$INSTANCE_NAME`_Disable();
+}
+
+void `$INSTANCE_NAME`_Init()
+{    
+    `$INSTANCE_NAME`_Enable();
+    
+}
+void `$INSTANCE_NAME`_Enable()
+{
+}
+
+void `$INSTANCE_NAME`_Disable()
+{
+}
+
+/* [] END OF FILE */
--- a/FluxEngine.cydsn/FIFOout/API/h.h
+++ b/FluxEngine.cydsn/FIFOout/API/h.h
@@ -0,0 +1,50 @@
+#if !defined(`$INSTANCE_NAME`_H)
+#define `$INSTANCE_NAME`_H
+
+#include "cytypes.h"
+#include "cyfitter.h"
+#include "CyLib.h" 
+
+#define `$INSTANCE_NAME`_FIFO_PTR	         ((reg8 *) `$INSTANCE_NAME`_dp__F0_REG)
+
+    /* Macros to clear DP FIFOs.*/
+#define `$INSTANCE_NAME`_CLEAR do { \
+    CY_SET_XTND_REG8(\
+        ((reg8 *) `$INSTANCE_NAME`_dp__DP_AUX_CTL_REG), 0x01u | \
+        CY_GET_XTND_REG8(((reg8 *) `$INSTANCE_NAME`_dp__DP_AUX_CTL_REG)));\
+    CY_SET_XTND_REG8(\
+        ((reg8 *) `$INSTANCE_NAME`_dp__DP_AUX_CTL_REG), 0xfeu & \
+        CY_GET_XTND_REG8(((reg8 *) `$INSTANCE_NAME`_dp__DP_AUX_CTL_REG)));\
+    } while(0)
+
+/* Macros to set FIFO level mode. See the TRM for details */
+#define `$INSTANCE_NAME`_SET_LEVEL_NORMAL \
+    CY_SET_XTND_REG8(\
+        ((reg8 *) `$INSTANCE_NAME`_dp__DP_AUX_CTL_REG), 0xfbu & \
+        CY_GET_XTND_REG8(((reg8 *) `$INSTANCE_NAME`_dp__DP_AUX_CTL_REG)))
+#define `$INSTANCE_NAME`_SET_LEVEL_MID \
+    CY_SET_XTND_REG8(\
+        ((reg8 *) `$INSTANCE_NAME`_dp__DP_AUX_CTL_REG), 0x04u | \
+        CY_GET_XTND_REG8(((reg8 *) `$INSTANCE_NAME`_dp__DP_AUX_CTL_REG)))
+
+/* Macros to set FIFO to single-buffer mode. */
+#define `$INSTANCE_NAME`_SINGLE_BUFFER_SET \
+    CY_SET_XTND_REG8(\
+        ((reg8 *) `$INSTANCE_NAME`_dp__DP_AUX_CTL_REG), 0x01u | \
+        CY_GET_XTND_REG8(((reg8 *) `$INSTANCE_NAME`_dp__DP_AUX_CTL_REG)))
+
+/* Macros to return the FIFO to normal mode. */
+#define `$INSTANCE_NAME`_SINGLE_BUFFER_UNSET \
+    CY_SET_XTND_REG8(\
+        ((reg8 *) `$INSTANCE_NAME`_dp__DP_AUX_CTL_REG), 0xfeu & \
+        CY_GET_XTND_REG8(((reg8 *) `$INSTANCE_NAME`_dp__DP_AUX_CTL_REG)))
+    
+void `$INSTANCE_NAME`_Enable();
+void `$INSTANCE_NAME`_Disable();
+void `$INSTANCE_NAME`_Start();
+void `$INSTANCE_NAME`_Stop();
+void `$INSTANCE_NAME`_Init();
+
+#endif
+
+/* [] END OF FILE */
--- a/FluxEngine.cydsn/FIFOout/FIFOout.cysym
+++ b/FluxEngine.cydsn/FIFOout/FIFOout.cysym
--- a/FluxEngine.cydsn/FIFOout/FIFOout.v
+++ b/FluxEngine.cydsn/FIFOout/FIFOout.v
@@ -0,0 +1,168 @@
+
+//`#start header` -- edit after this line, do not edit this line
+`include "cypress.v"
+//`#end` -- edit above this line, do not edit this line
+// Generated on 11/16/2017 at 15:44
+// Component: FIFOout
+module FIFOout (
+    input req,
+	input clk,
+    output [7:0] d,
+	output drq,
+	output empty,
+    output ack
+);
+
+//`#start body` -- edit after this line, do not edit this line
+
+/* Reads from the FIFO are done based on the FIFO being not empty. */
+ 
+wire [7:0] po;
+assign d = po;
+
+localparam STATE_WAITFORREQ    = 1'b0;
+localparam STATE_READ          = 1'b1;
+
+reg state;
+reg oldreq;
+
+assign ack = (state != STATE_READ);
+
+always @(posedge clk)
+begin
+    case (state)
+        STATE_WAITFORREQ:
+        begin
+            if (!empty)
+            begin
+                if (req && !oldreq)
+                begin
+                    state <= STATE_READ;
+                end
+                oldreq <= req;
+            end
+        end
+        
+        STATE_READ:
+        begin
+            state <= STATE_WAITFORREQ;
+        end
+    endcase
+end
+            
+cy_psoc3_dp #(.cy_dpconfig(
+{
+    `CS_ALU_OP_PASS, `CS_SRCA_A0, `CS_SRCB_D0,
+    `CS_SHFT_OP_PASS, `CS_A0_SRC_NONE, `CS_A1_SRC_NONE,
+    `CS_FEEDBACK_DSBL, `CS_CI_SEL_CFGA, `CS_SI_SEL_CFGA,
+    `CS_CMP_SEL_CFGA, /*CFGRAM0: STATE_WAITFORREQ*/
+    `CS_ALU_OP_PASS, `CS_SRCA_A0, `CS_SRCB_D0,
+    `CS_SHFT_OP_PASS, `CS_A0_SRC___F0, `CS_A1_SRC_NONE,
+    `CS_FEEDBACK_DSBL, `CS_CI_SEL_CFGA, `CS_SI_SEL_CFGA,
+    `CS_CMP_SEL_CFGA, /*CFGRAM1: STATE_LOAD*/
+    `CS_ALU_OP_PASS, `CS_SRCA_A0, `CS_SRCB_D0,
+    `CS_SHFT_OP_PASS, `CS_A0_SRC_NONE, `CS_A1_SRC_NONE,
+    `CS_FEEDBACK_DSBL, `CS_CI_SEL_CFGA, `CS_SI_SEL_CFGA,
+    `CS_CMP_SEL_CFGA, /*CFGRAM2:           */
+    `CS_ALU_OP_PASS, `CS_SRCA_A0, `CS_SRCB_D0,
+    `CS_SHFT_OP_PASS, `CS_A0_SRC_NONE, `CS_A1_SRC_NONE,
+    `CS_FEEDBACK_DSBL, `CS_CI_SEL_CFGA, `CS_SI_SEL_CFGA,
+    `CS_CMP_SEL_CFGA, /*CFGRAM3:           */
+    `CS_ALU_OP_PASS, `CS_SRCA_A0, `CS_SRCB_D0,
+    `CS_SHFT_OP_PASS, `CS_A0_SRC_NONE, `CS_A1_SRC_NONE,
+    `CS_FEEDBACK_DSBL, `CS_CI_SEL_CFGA, `CS_SI_SEL_CFGA,
+    `CS_CMP_SEL_CFGA, /*CFGRAM4:           */
+    `CS_ALU_OP_PASS, `CS_SRCA_A0, `CS_SRCB_D0,
+    `CS_SHFT_OP_PASS, `CS_A0_SRC_NONE, `CS_A1_SRC_NONE,
+    `CS_FEEDBACK_DSBL, `CS_CI_SEL_CFGA, `CS_SI_SEL_CFGA,
+    `CS_CMP_SEL_CFGA, /*CFGRAM5:           */
+    `CS_ALU_OP_PASS, `CS_SRCA_A0, `CS_SRCB_D0,
+    `CS_SHFT_OP_PASS, `CS_A0_SRC_NONE, `CS_A1_SRC_NONE,
+    `CS_FEEDBACK_DSBL, `CS_CI_SEL_CFGA, `CS_SI_SEL_CFGA,
+    `CS_CMP_SEL_CFGA, /*CFGRAM6:           */
+    `CS_ALU_OP_PASS, `CS_SRCA_A0, `CS_SRCB_D0,
+    `CS_SHFT_OP_PASS, `CS_A0_SRC_NONE, `CS_A1_SRC_NONE,
+    `CS_FEEDBACK_DSBL, `CS_CI_SEL_CFGA, `CS_SI_SEL_CFGA,
+    `CS_CMP_SEL_CFGA, /*CFGRAM7:           */
+    8'hFF, 8'h00,  /*CFG9:           */
+    8'hFF, 8'hFF,  /*CFG11-10:           */
+    `SC_CMPB_A1_D1, `SC_CMPA_A1_D1, `SC_CI_B_ARITH,
+    `SC_CI_A_ARITH, `SC_C1_MASK_DSBL, `SC_C0_MASK_DSBL,
+    `SC_A_MASK_DSBL, `SC_DEF_SI_0, `SC_SI_B_DEFSI,
+    `SC_SI_A_DEFSI, /*CFG13-12:           */
+    `SC_A0_SRC_ACC, `SC_SHIFT_SL, 1'h0,
+    1'h0, `SC_FIFO1_BUS, `SC_FIFO0_BUS,
+    `SC_MSB_DSBL, `SC_MSB_BIT0, `SC_MSB_NOCHN,
+    `SC_FB_NOCHN, `SC_CMP1_NOCHN,
+    `SC_CMP0_NOCHN, /*CFG15-14:           */
+    10'h00, `SC_FIFO_CLK__DP,`SC_FIFO_CAP_AX,
+    `SC_FIFO_LEVEL,`SC_FIFO_ASYNC,`SC_EXTCRC_DSBL,
+    `SC_WRK16CAT_DSBL /*CFG17-16:           */
+}
+)) dp(
+        /*  input                   */  .reset(1'b0),
+        /*  input                   */  .clk(clk),
+        /*  input   [02:00]         */  .cs_addr({2'b0, state}),
+        /*  input                   */  .route_si(1'b0),
+        /*  input                   */  .route_ci(1'b0),
+        /*  input                   */  .f0_load(1'b0),
+        /*  input                   */  .f1_load(1'b0),
+        /*  input                   */  .d0_load(1'b0),
+        /*  input                   */  .d1_load(1'b0),
+        /*  output                  */  .ce0(),
+        /*  output                  */  .cl0(),
+        /*  output                  */  .z0(),
+        /*  output                  */  .ff0(),
+        /*  output                  */  .ce1(),
+        /*  output                  */  .cl1(),
+        /*  output                  */  .z1(),
+        /*  output                  */  .ff1(),
+        /*  output                  */  .ov_msb(),
+        /*  output                  */  .co_msb(),
+        /*  output                  */  .cmsb(),
+        /*  output                  */  .so(),
+        /*  output                  */  .f0_bus_stat(drq), // not full
+        /*  output                  */  .f0_blk_stat(empty), // empty
+        /*  output                  */  .f1_bus_stat(),
+        /*  output                  */  .f1_blk_stat(),
+        
+        /* input                    */  .ci(1'b0),     // Carry in from previous stage
+        /* output                   */  .co(),// Carry out to next stage
+        /* input                    */  .sir(1'b0),    // Shift in from right side
+        /* output                   */  .sor(),        // Shift out to right side
+        /* input                    */  .sil(1'b0),    // Shift in from left side
+        /* output                   */  .sol(),        // Shift out to left side
+        /* input                    */  .msbi(1'b0),   // MSB chain in
+        /* output                   */  .msbo(),       // MSB chain out
+        /* input [01:00]            */  .cei(2'b0),    // Compare equal in from prev stage
+        /* output [01:00]           */  .ceo(),        // Compare equal out to next stage
+        /* input [01:00]            */  .cli(2'b0),    // Compare less than in from prv stage
+        /* output [01:00]           */  .clo(),        // Compare less than out to next stage
+        /* input [01:00]            */  .zi(2'b0),     // Zero detect in from previous stage
+        /* output [01:00]           */  .zo(),         // Zero detect out to next stage
+        /* input [01:00]            */  .fi(2'b0),     // 0xFF detect in from previous stage
+        /* output [01:00]           */  .fo(),         // 0xFF detect out to next stage
+        /* input [01:00]            */  .capi(2'b0),   // Software capture from previous stage
+        /* output [01:00]           */  .capo(),       // Software capture to next stage
+        /* input                    */  .cfbi(1'b0),   // CRC Feedback in from previous stage
+        /* output                   */  .cfbo(),       // CRC Feedback out to next stage
+        /* input [07:00]            */  .pi(8'b0),     // Parallel data port
+        /* output [07:00]           */  .po(po)       // Parallel data port
+);
+
+//`#end` -- edit above this line, do not edit this line
+endmodule
+//`#start footer` -- edit after this line, do not edit this line
+//`#end` -- edit above this line, do not edit this line
+
+
+
+
+
+
+
+
+
+
+
+
--- a/FluxEngine.cydsn/FluxEngine.cydwr
+++ b/FluxEngine.cydsn/FluxEngine.cydwr
@@ -28,6 +28,30 @@
        <Data key="sync_with_bus_clk" value="True" />
        <Data key="user_set_domain" value="False" />
      </Group>
+      <Group key="1a7e8637-3b6b-4e84-839c-0dfc18fdaf5b">
+        <Data key="check_tolerance" value="True" />
+        <Data key="clock_version" value="v1" />
+        <Data key="derive_type" value="NAMED_DIVIDER" />
+        <Data key="desired_freq" value="0" />
+        <Data key="desired_unit" value="15" />
+        <Data key="divider" value="0" />
+        <Data key="domain" value="DIGITAL" />
+        <Data key="enabled" value="True" />
+        <Data key="minus_accuracy" value="0.25" />
+        <Data key="minus_tolerance" value="5" />
+        <Data key="name" value="Clock_5" />
+        <Data key="named_src_direct_connect" value="True" />
+        <Data key="netlist_name" value="Clock_5" />
+        <Data key="placement" value="AUTO" />
+        <Data key="plus_accuracy" value="0.25" />
+        <Data key="plus_tolerance" value="5" />
+        <Data key="scope" value="LOCAL" />
+        <Data key="src_clk_id" value="75C2148C-3656-4d8a-846D-0CAE99AB6FF7" />
+        <Data key="src_clk_name" value="BUS_CLK" />
+        <Data key="start_on_reset" value="True" />
+        <Data key="sync_with_bus_clk" value="True" />
+        <Data key="user_set_domain" value="False" />
+      </Group>
      <Group key="4eef02b9-8ad1-43c4-85f1-b3335faa5fc4">
        <Data key="check_tolerance" value="True" />
        <Data key="clock_version" value="v1" />
@@ -609,6 +633,7 @@
  <Group key="DWRInstGuidMapping">
    <Group key="Clock">
      <Data key="0b2f9bbb-00ce-4115-a788-ffb9d046a9e5" value="Clock_4" />
+      <Data key="1a7e8637-3b6b-4e84-839c-0dfc18fdaf5b" value="Clock_5" />
      <Data key="4eef02b9-8ad1-43c4-85f1-b3335faa5fc4" value="Clock_3" />
      <Data key="06c4d5d4-f15f-4b29-a1d0-c24b2e38b1ec" value="CounterClock" />
      <Data key="24cd38f7-f472-4403-837f-86807c8f5333" value="PULSE_CLOCK" />
@@ -638,13 +663,14 @@
      <Data key="a5d987c6-e45b-45b9-ad93-656fab06d720" value="TRK00" />
      <Data key="a93ef5b3-00f4-42c0-8fad-0e275a7e2537" value="MOTEB" />
      <Data key="b8380fb7-fdb8-449f-bd8d-c4ca96cdf55a" value="DEBUG_PINS" />
+      <Data key="bc2e8987-db82-469c-bf6f-22fd3464cc70" value="DEBUG_PINS" />
      <Data key="bc5d52a1-1b25-4aa0-9ba9-3f81d122772f" value="DEBUG_PINS" />
      <Data key="beca5e2d-f70f-4900-a4db-7eca1ed3126e/8b77a6c4-10a0-4390-971c-672353e2a49c" value="USBFS_Dm" />
      <Data key="beca5e2d-f70f-4900-a4db-7eca1ed3126e/618a72fc-5ddd-4df5-958f-a3d55102db42" value="USBFS_Dp" />
      <Data key="c5367cde-21d5-4866-9a32-d16abfea0c61" value="WPT" />
      <Data key="d19368c5-6855-41bb-a9ff-808938abef00" value="INDEX" />
      <Data key="e9f14b5a-b2bf-49b8-98f3-d7b5a43ace8d" value="DRVSB" />
-      <Data key="e851a3b9-efb8-48be-bbb8-b303b216c393" value="LED" />
+      <Data key="e851a3b9-efb8-48be-bbb8-b303b216c393" value="LED_PIN" />
      <Data key="e51063a9-4fad-40c7-a06b-7cc4b137dc18" value="DSKCHG" />
      <Data key="ea7ee228-8b3f-426c-8bb8-cd7a81937769" value="DIR" />
      <Data key="ed092b9b-d398-4703-be89-cebf998501f6" value="UartTx" />
@@ -3859,6 +3885,32 @@
        <Data key="Port Format" value="2,3" />
      </Group>
    </Group>
+    <Group key="bc2e8987-db82-469c-bf6f-22fd3464cc70">
+      <Group key="0">
+        <Data key="Port Format" value="0,0" />
+      </Group>
+      <Group key="1">
+        <Data key="Port Format" value="0,1" />
+      </Group>
+      <Group key="2">
+        <Data key="Port Format" value="0,2" />
+      </Group>
+      <Group key="3">
+        <Data key="Port Format" value="0,3" />
+      </Group>
+      <Group key="4">
+        <Data key="Port Format" value="0,4" />
+      </Group>
+      <Group key="5">
+        <Data key="Port Format" value="0,5" />
+      </Group>
+      <Group key="6">
+        <Data key="Port Format" value="0,6" />
+      </Group>
+      <Group key="7">
+        <Data key="Port Format" value="0,7" />
+      </Group>
+    </Group>
    <Group key="bc5d52a1-1b25-4aa0-9ba9-3f81d122772f">
      <Group key="0">
        <Data key="Port Format" value="0,5" />
@@ -3914,7 +3966,7 @@
    </Group>
    <Group key="fbd1f839-40f9-498e-a48b-5f3048ea5c3d/52f31aa9-2f0a-497d-9a1f-1424095e13e6">
      <Group key="0">
-        <Data key="Port Format" value="2,5" />
+        <Data key="Port Format" value="12,7" />
      </Group>
    </Group>
    <Group key="fede1767-f3fd-4021-b3d7-8f9d88f36f9b">
--- a/FluxEngine.cydsn/FluxEngine.cyprj
+++ b/FluxEngine.cydsn/FluxEngine.cyprj
--- a/FluxEngine.cydsn/UdbSequencer/UdbSequencer.cysym
+++ b/FluxEngine.cydsn/UdbSequencer/UdbSequencer.cysym
--- a/FluxEngine.cydsn/Sequencer/Sequencer.v
+++ b/FluxEngine.cydsn/Sequencer/Sequencer.v
@@ -0,0 +1,101 @@
+
+//`#start header` -- edit after this line, do not edit this line
+`include "cypress.v"
+//`#end` -- edit above this line, do not edit this line
+// Generated on 11/24/2019 at 17:25
+// Component: Sequencer
+module Sequencer (
+	output req, /* request new data on leading edge */
+	output wdata,
+    output [2:0] debug_state,
+	input clock,
+	input dataclock, /* incoming data on leading edge */
+	input [7:0] opcode,
+    input index,
+    input sampleclock,
+    input reset
+);
+
+//`#start body` -- edit after this line, do not edit this line
+
+localparam STATE_IDLE = 0;
+localparam STATE_LOAD = 1;
+localparam STATE_WAITING = 2;
+localparam STATE_PULSING = 3;
+localparam STATE_INDEXING = 4;
+
+localparam OPCODE_PULSE = 8'h80;
+localparam OPCODE_INDEX = 8'h81;
+
+reg [2:0] state;
+reg [6:0] countdown;
+
+assign req = (state == STATE_LOAD);
+assign wdata = (state == STATE_PULSING);
+assign debug_state = state;
+
+reg olddataclock;
+wire dataclocked;
+always @(posedge clock) olddataclock <= dataclock;
+assign dataclocked = !olddataclock && dataclock;
+
+reg oldsampleclock;
+wire sampleclocked;
+always @(posedge clock) oldsampleclock <= sampleclock;
+assign sampleclocked = !oldsampleclock && sampleclock;
+
+reg oldindex;
+wire indexed;
+always @(posedge clock) oldindex <= index;
+assign indexed = !oldindex && index;
+
+always @(posedge clock)
+begin
+    if (reset)
+    begin
+        state <= STATE_IDLE;
+        countdown <= 0;
+    end
+    else
+        case (state)
+            STATE_IDLE:
+                state <= STATE_LOAD;
+            
+            STATE_LOAD:
+                if (dataclocked)
+                    case (opcode)
+                        OPCODE_PULSE:
+                            state <= STATE_PULSING;
+                        
+                        OPCODE_INDEX:
+                            state <= STATE_INDEXING;
+                        
+                        default:
+                        begin
+                            countdown <= opcode[6:0];
+                            state <= STATE_WAITING;
+                        end
+                    endcase
+            
+            STATE_WAITING:
+                if (sampleclocked)
+                begin
+                    if (countdown == 0)
+                        state <= STATE_LOAD;
+                    else
+                        countdown <= countdown - 1;
+                end
+            
+            STATE_PULSING:
+                state <= STATE_LOAD;
+            
+            STATE_INDEXING:
+                if (indexed)
+                    state <= STATE_LOAD;
+        endcase
+end
+
+//`#end` -- edit above this line, do not edit this line
+endmodule
+//`#start footer` -- edit after this line, do not edit this line
+//`#end` -- edit above this line, do not edit this line
--- a/FluxEngine.cydsn/TopDesign/TopDesign.cysch
+++ b/FluxEngine.cydsn/TopDesign/TopDesign.cysch
--- a/FluxEngine.cydsn/UdbSampler/UdbSampler.cyudb
+++ b/FluxEngine.cydsn/UdbSampler/UdbSampler.cyudb
--- a/FluxEngine.cydsn/UdbSequencer/UdbSequencer.cyudb
+++ b/FluxEngine.cydsn/UdbSequencer/UdbSequencer.cyudb
--- a/FluxEngine.cydsn/main.c
+++ b/FluxEngine.cydsn/main.c
@@ -99,6 +99,15 @@ static void start_motor(void)
    CyWdtClear();
 }

+static void stop_motor(void)
+{
+    if (motor_on)
+    {
+        MOTOR_REG_Write(0);
+        motor_on = false;
+    }
+}
+
 static void wait_until_writeable(int ep)
 {
    while (USBFS_GetEPState(ep) != USBFS_IN_BUFFER_EMPTY)
@@ -138,25 +147,36 @@ static void cmd_get_version(struct any_frame* f)

 static void step(int dir)
 {
-    STEP_REG_Write(dir);
-    CyDelayUs(1);
-    STEP_REG_Write(dir | 2);
-    CyDelayUs(1);
-    STEP_REG_Write(dir);
+    STEP_REG_Write(dir); /* step high */
+    CyDelayUs(6);
+    STEP_REG_Write(dir | 2); /* step low */
+    CyDelayUs(6);
+    STEP_REG_Write(dir); /* step high again, drive moves now */
    CyDelay(STEP_INTERVAL_TIME);
 }

+static void home(void)
+{
+    for (int i=0; i<100; i++)
+    {
+        /* Don't keep stepping forever, because if a drive's
+         * not connected bad things happen. */
+        if (TRACK0_REG_Read())
+            break;
+        step(STEP_TOWARDS0);
+    }
+    
+    /* Step to -1, which should be a nop, to reset the disk on disk change. */
+    step(STEP_TOWARDS0);
+}
+
 static void seek_to(int track)
 {
    start_motor();
-    if (!homed)
+    if (!homed || (track == 0))
    {
        print("homing");
-        while (!TRACK0_REG_Read())
-            step(STEP_TOWARDS0);
-            
-        /* Step to -1, which should be a nop, to reset the disk on disk change. */
-        step(STEP_TOWARDS0);
+        home();
        
        homed = true;
        current_track = 0;
@@ -167,11 +187,7 @@ static void seek_to(int track)
    while (track != current_track)
    {
        if (TRACK0_REG_Read())
-        {
-            if (current_track != 0)
-                print("unexpectedly detected track 0");
            current_track = 0;
-        }
        
        if (track > current_track)
        {
@@ -291,7 +307,6 @@ static void cmd_read(struct read_frame* f)

    /* Wait for the beginning of a rotation. */
        
-    print("wait");
    index_irq = false;
    while (!index_irq)
        ;
@@ -306,7 +321,6 @@ static void cmd_read(struct read_frame* f)
    dma_underrun = false;
    int count = 0;
    SAMPLER_CONTROL_Write(0); /* !reset */
-    CAPTURE_CONTROL_Write(1);
    CyDmaChSetInitialTd(dma_channel, td[dma_writing_to_td]);
    CyDmaClearPendingDrq(dma_channel);
    CyDmaChEnable(dma_channel, 1);
@@ -366,7 +380,6 @@ static void cmd_read(struct read_frame* f)
        dma_reading_from_td = NEXT_BUFFER(dma_reading_from_td);
    }
 abort:;
-    CAPTURE_CONTROL_Write(0);
    CyDmaChSetRequest(dma_channel, CY_DMA_CPU_TERM_CHAIN);
    while (CyDmaChGetRequest(dma_channel))
        ;
@@ -412,25 +425,28 @@ static void init_replay_dma(void)

        CyDmaTdSetConfiguration(td[i], BUFFER_SIZE, td[nexti],
            CY_DMA_TD_INC_SRC_ADR | SEQUENCER_DMA__TD_TERMOUT_EN);
-        CyDmaTdSetAddress(td[i], LO16((uint32)&dma_buffer[i]), LO16((uint32)&SEQUENCER_DATAPATH_F0_REG));
+        CyDmaTdSetAddress(td[i], LO16((uint32)&dma_buffer[i]), LO16((uint32)REPLAY_FIFO_FIFO_PTR));
    }    
 }

 static void cmd_write(struct write_frame* f)
 {
+    print("cmd_write");
+    
    if (f->bytes_to_write % FRAME_SIZE)
    {
        send_error(F_ERROR_INVALID_VALUE);
        return;
    }
    
+    SEQUENCER_CONTROL_Write(1); /* put the sequencer into reset */
+
    SIDE_REG_Write(f->side);
-    SEQUENCER_CONTROL_Write(1); /* reset */
    {
-        uint8_t i = CyEnterCriticalSection();
-        SEQUENCER_DATAPATH_F0_SET_LEVEL_NORMAL;
-        SEQUENCER_DATAPATH_F0_CLEAR;
-        SEQUENCER_DATAPATH_F0_SINGLE_BUFFER_UNSET;
+        uint8_t i = CyEnterCriticalSection();        
+        REPLAY_FIFO_SET_LEVEL_NORMAL;
+        REPLAY_FIFO_CLEAR;
+        REPLAY_FIFO_SINGLE_BUFFER_UNSET;
        CyExitCriticalSection(i);
    }
    seek_to(current_track);    
@@ -555,7 +571,7 @@ abort:
        CyDmaChDisable(dma_channel);
    }
    
-    //debug("p=%d cr=%d cw=%d f=%d l=%d w=%d index=%d underrun=%d", packets, count_read, count_written, finished, listening, writing, index_irq, dma_underrun);
+    print("p=%d cr=%d cw=%d f=%d w=%d index=%d underrun=%d", packets, count_read, count_written, finished, writing, index_irq, dma_underrun);
    if (!finished)
    {
        while (count_read < packets)
@@ -573,6 +589,7 @@ abort:
    }
    
    deinit_dma();
+    print("write finished");
    
    if (dma_underrun)
    {
@@ -605,19 +622,113 @@ static void cmd_erase(struct erase_frame* f)
    send_reply((struct any_frame*) &r);
 }

+static void set_drive_flags(uint8_t flags)
+{
+    if (current_drive_flags != flags)
+        homed = false;
+    
+    current_drive_flags = flags;
+    DRIVESELECT_REG_Write((flags & 1) ? 2 : 1); /* select drive 1 or 0 */
+    DENSITY_REG_Write(flags >> 1); /* density bit */
+}
+
 static void cmd_set_drive(struct set_drive_frame* f)
 {
-    if (current_drive_flags != f->drive_flags)
-    {
-        current_drive_flags = f->drive_flags;
-        DRIVE_REG_Write(current_drive_flags);
-        homed = false;
-    }
+    set_drive_flags(f->drive_flags);
    
    DECLARE_REPLY_FRAME(struct any_frame, F_FRAME_SET_DRIVE_REPLY);
    send_reply((struct any_frame*) &r);
 }
-   
+
+static uint16_t read_output_voltage_mv(void)
+{
+    OUTPUT_VOLTAGE_ADC_StartConvert();
+    OUTPUT_VOLTAGE_ADC_IsEndConversion(OUTPUT_VOLTAGE_ADC_WAIT_FOR_RESULT);
+    uint16_t samples = OUTPUT_VOLTAGE_ADC_GetResult16();
+    return OUTPUT_VOLTAGE_ADC_CountsTo_mVolts(samples);
+}
+
+static void read_output_voltages(struct voltages* v)
+{
+    SIDE_REG_Write(1); /* set DIR to low (remember this is inverted) */
+    CyDelay(100);
+    v->logic0_mv = read_output_voltage_mv();
+
+    SIDE_REG_Write(0);
+    CyDelay(100);
+    v->logic1_mv = read_output_voltage_mv();
+}
+
+static uint16_t read_input_voltage_mv(void)
+{
+    INPUT_VOLTAGE_ADC_StartConvert();
+    INPUT_VOLTAGE_ADC_IsEndConversion(INPUT_VOLTAGE_ADC_WAIT_FOR_RESULT);
+    uint16_t samples = INPUT_VOLTAGE_ADC_GetResult16();
+    return INPUT_VOLTAGE_ADC_CountsTo_mVolts(samples);
+}
+
+static void read_input_voltages(struct voltages* v)
+{
+    home();
+    CyDelay(50);
+    v->logic0_mv = read_input_voltage_mv();
+    
+    step(STEP_AWAYFROM0);
+    CyDelay(50);
+    v->logic1_mv = read_input_voltage_mv();
+}
+
+static void cmd_measure_voltages(void)
+{
+    stop_motor();
+    INPUT_VOLTAGE_ADC_Start();
+    INPUT_VOLTAGE_ADC_SetPower(INPUT_VOLTAGE_ADC__HIGHPOWER);
+    OUTPUT_VOLTAGE_ADC_Start();
+    OUTPUT_VOLTAGE_ADC_SetPower(OUTPUT_VOLTAGE_ADC__HIGHPOWER);
+    
+    DECLARE_REPLY_FRAME(struct voltages_frame, F_FRAME_MEASURE_VOLTAGES_REPLY);
+    
+    CyWdtClear();
+    MOTOR_REG_Write(0); /* should be ignored anyway */
+    DRIVESELECT_REG_Write(0); /* deselect both drives */
+    CyDelay(200); /* wait for things to settle */
+    read_output_voltages(&r.output_both_off);
+    read_input_voltages(&r.input_both_off);
+
+    CyWdtClear();
+    DRIVESELECT_REG_Write(1); /* select drive 0 */
+    CyDelay(50);
+    read_output_voltages(&r.output_drive_0_selected);
+    read_input_voltages(&r.input_drive_0_selected);
+    MOTOR_REG_Write(1);
+    CyDelay(300);
+    CyWdtClear();
+    read_output_voltages(&r.output_drive_0_running);
+    read_input_voltages(&r.input_drive_0_running);
+    MOTOR_REG_Write(0);
+    CyDelay(300);
+    
+    CyWdtClear();
+    DRIVESELECT_REG_Write(2); /* select drive 1 */
+    CyDelay(50);
+    read_output_voltages(&r.output_drive_1_selected);
+    read_input_voltages(&r.input_drive_1_selected);
+    MOTOR_REG_Write(1);
+    CyDelay(300);
+    CyWdtClear();
+    read_output_voltages(&r.output_drive_1_running);
+    read_input_voltages(&r.input_drive_1_running);
+    MOTOR_REG_Write(0);
+    CyDelay(300);
+
+    CyWdtClear();
+    DRIVESELECT_REG_Write(0);
+    homed = false;
+    INPUT_VOLTAGE_ADC_Stop();
+    OUTPUT_VOLTAGE_ADC_Stop();
+    send_reply((struct any_frame*) &r);
+}
+
 static void handle_command(void)
 {
    static uint8_t input_buffer[FRAME_SIZE];
@@ -662,6 +773,10 @@ static void handle_command(void)
        case F_FRAME_SET_DRIVE_CMD:
            cmd_set_drive((struct set_drive_frame*) f);
            break;
+        
+        case F_FRAME_MEASURE_VOLTAGES_CMD:
+            cmd_measure_voltages();
+            break;
            
        default:
            send_error(F_ERROR_BAD_COMMAND);
@@ -676,7 +791,9 @@ int main(void)
    INDEX_IRQ_StartEx(&index_irq_cb);
    CAPTURE_DMA_FINISHED_IRQ_StartEx(&capture_dma_finished_irq_cb);
    SEQUENCER_DMA_FINISHED_IRQ_StartEx(&replay_dma_finished_irq_cb);
-    DRIVE_REG_Write(0);
+    INPUT_VOLTAGE_ADC_Stop();
+    OUTPUT_VOLTAGE_ADC_Stop();
+    DRIVESELECT_REG_Write(0);
    UART_Start();
    USBFS_Start(0, USBFS_DWR_VDDD_OPERATION);
    
@@ -709,6 +826,7 @@ int main(void)
        
        if (USBFS_GetEPState(FLUXENGINE_CMD_OUT_EP_NUM) == USBFS_OUT_BUFFER_FULL)
        {
+            set_drive_flags(current_drive_flags);
            handle_command();
            USBFS_EnableOutEP(FLUXENGINE_CMD_OUT_EP_NUM);
            print("idle");
--- a/4
+++ b/4
@@ -1,8 +1,8 @@
 PACKAGES = zlib sqlite3 libusb-1.0

-export CFLAGS = -O3 -g --std=c++14 \
+export CFLAGS = -Os -g --std=c++14 \
 	-ffunction-sections -fdata-sections
-export LDFLAGS = -O3
+export LDFLAGS = -Os

 ifeq ($(OS), Windows_NT)
 export CXX = /mingw32/bin/g++
--- a/arch/ibm/decoder.cc
+++ b/arch/ibm/decoder.cc
@@ -134,6 +134,9 @@ void IbmDecoder::decodeSectorRecord()
    uint16_t gotCrc = crc16(CCITT_POLY, bytes.slice(0, _currentHeaderLength + 5));
    if (wantCrc == gotCrc)
        _sector->status = Sector::DATA_MISSING; /* correct but unintuitive */
+
+    if (_ignoreSideByte)
+        _sector->logicalSide = _sector->physicalSide;
 }

 void IbmDecoder::decodeDataRecord()
--- a/arch/ibm/ibm.h
+++ b/arch/ibm/ibm.h
@@ -31,8 +31,9 @@ struct IbmIdam
 class IbmDecoder : public AbstractDecoder
 {
 public:
-    IbmDecoder(unsigned sectorBase):
-        _sectorBase(sectorBase)
+    IbmDecoder(unsigned sectorBase, bool ignoreSideByte=false):
+        _sectorBase(sectorBase),
+        _ignoreSideByte(ignoreSideByte)
    {}

    RecordType advanceToNextRecord();
@@ -41,6 +42,7 @@ public:

 private:
    unsigned _sectorBase;
+    bool _ignoreSideByte;
    unsigned _currentSectorSize;
    unsigned _currentHeaderLength;
 };
--- a/doc/building.md
+++ b/doc/building.md
@@ -103,7 +103,43 @@ the unconnected pins and solder a short piece of wire to a GND pin on the
 board. Alternatively you'll need to splice it into your drive's power supply
 cable somehow. (The black one.)

-## Building the firmware
+## Programming the board
+
+You've got two options here. You can either use the precompiled firmware
+supplied with the source, or else install the Cypress SDK and build it
+yourself. If you want to hack the firmware source you need the latter, but
+if you trust me to do it for you use the precompiled firmware. In either
+case you'll need Windows and have to install some Cypress stuff.
+
+**Before you read this:** If you're on Windows, good news! You can download a
+precompiled version of the FluxEngine client and precompiled firmware [from
+the GitHub releases
+page](https://github.com/davidgiven/fluxengine/releases/latest). Simply unzip
+it somewhere and run the `.exe` files from a `cmd` window (or other shell).
+Follow the instructions below to program the board with the firmware.
+
+### Using the precompiled firmware
+
+On your Windows machine, [install the PSoC
+Programmer](https://www.cypress.com/products/psoc-programming-solutions).
+**Note:** _not_ the Cypress Programmer, which is for a different board!
+Cypress will make you register.
+
+Once done, run it. Plug the blunt end of the FluxEngine board into a USB
+port (the end which is a USB connector). The programmer should detect it
+and report it as a KitProg. You may be prompted to upgrade the programmer
+hardware; if so, follow the instructions and do it.
+
+Now go to File -> File Load and open
+`FluxEngine.cydsn/CortexM3/ARM_GCC_541/Release/FluxEngine.hex` in the
+project. If you're on Windows, the precompiled zipfile also contains a copy
+of this file. Press the Program button (the one in the toolbar marked with a
+down arrow). Stuff will happen and you should be left with three green boxes
+in the status bar and 'Programming Succeeded' at the top of the log window.
+
+You're done. You can unplug the board and close the programmer.
+
+### Building the firmware yourself

 On your Windows machine, [install the Cypress SDK and CY8CKIT-059
 BSP](http://www.cypress.com/documentation/development-kitsboards/cy8ckit-059-psoc-5lp-prototyping-kit-onboard-programmer-and).
@@ -118,7 +154,7 @@ tutorial and making the LED on your board flash. It'll tell you where all the
 controls are and how to program the board. Remember that the big end of the
 board plugs into your computer for programming.

-When you're ready, open the `FluxEngine.cydsn/FluxEngine.cywrk` workspace,
+When you're ready, open the `FluxEngine.cydsn/FluxEngine.cyprj` project,
 pick 'Program' from the menu, and the firmware should compile and be
 programmed onto your board.

@@ -139,11 +175,6 @@ the port and proceed normally.

 ## Building the client

-**Before you read this:** If you're on Windows, good news! You can download a
-*precompiled version of the FluxEngine client [from the GitHub releases
-*page](https://github.com/davidgiven/fluxengine/releases/latest). Simply unzip
-*it somewhere and run it from a `cmd` window (or other shell).
-
 The client software is where the intelligence, such as it is, is. It's pretty
 generic libusb stuff and should build and run on Windows, Linux and OSX as
 well, although on Windows it'll need MSYS2 and mingw32. You'll need to
--- a/doc/disk-brother.md
+++ b/doc/disk-brother.md
@@ -129,8 +129,8 @@ reverse engineered it to find out.

 Standard Linux mtools will access the filesystem image and allow you to move
 files in and out. However, you'll need to change the media type bytes at
-offsets 0x015 and 0x100 from 0x58 to 0xf0 before mtools will touch it. Once
-done, this will work:
+offsets 0x015 and 0x100 from 0x58 to 0xf0 before mtools will touch it. The
+supplied `brother240tool` will do this. Once done, this will work:

 ```
 mdir -i brother.img
--- a/doc/technical.md
+++ b/doc/technical.md
@@ -123,8 +123,12 @@ admittedly expensive.)
    sheet](http://www.bitsavers.org/pdf/mitsubishi/floppy/M4851/TJ2-G30211A_M4851_DSHH_48TPI_OEM_Manual_Nov83.pdf):
    the equivalent data sheet for a representative 5.25" drive.

+  - [The DRG Business Machines YD-174 manual](https://electrickery.hosting.philpem.me.uk/comp/divcomp/doc/YE_Data_YD-174_8inchFloppyDriveTechnicalManual.pdf):
+	the equivalent manual (data sheets hadn't been invented then) for a
+	representative 8" drive.
+
  - [KryoFlux stream file
    documentation](https://www.kryoflux.com/download/kryoflux_stream_protocol_rev1.1.pdf):
    the format of KryoFlux stream files (partially supported by FluxEngine)

-  
+  
--- a/doc/using.md
+++ b/doc/using.md
@@ -51,7 +51,7 @@ In order to do anything useful, you have to plug it in to a floppy disk drive (o
     rpm for a 3.5" disk, or 360 rpm for a 5.25" disk. If it doesn't, please
     [get in touch](https://github.com/davidgiven/fluxengine/issues/new).

-  7. Do `fluxengine testbulktransport` from the shell. It'll measure your USB
+  7. Do `fluxengine test bulktransport` from the shell. It'll measure your USB
     bandwidth. Ideally you should be getting above 900kB/s. FluxEngine needs
     about 850kB/s, so if you're getting less than this, try a different USB
     port.
@@ -213,18 +213,50 @@ directory.
  - `fluxengine seek`: moves the head. Mainly useful for finding out whether
  your drive can seek to track 82. (Mine can't.)

-  - `fluxengine testbulktransport`: measures your USB throughput. You need
+  - `fluxengine test bulktransport`: measures your USB throughput. You need
  about 600kB/s for FluxEngine to work. You don't need a disk in the drive
  for this one.

+  - `fluxengine test voltages`: measures your FDD bus signal voltages, which
+  is useful for testing for termination issues.
+
  - `fluxengine upgradefluxfile`: occasionally I need to upgrade the flux
  file format in a non-backwards-compatible way; this tool will upgrade flux
  files to the new format.

+  - `fluxengine convert`: converts flux files from various formats to various
+  other formats. You can use this to convert Catweasel flux files to
+  FluxEngine's native format, FluxEngine flux files to various other formats
+  useful for debugging (including VCD which can be loaded into
+  [sigrok](http://sigrok.org)), and bidirectional conversion to and from
+  Supercard Pro `.scp` format.
+
+  **Important SCP note:** import (`fluxengine convert scptoflux`) should be
+  fairly robust, but export (`fluxengine convert fluxtoscp`) should only be
+  done with great caution as FluxEngine files contain features which can't be
+  represented very well in `.scp` format and they're probably pretty dubious.
+  As ever, please [get in
+  touch](https://github.com/davidgiven/fluxengine/issues/new) with any reports.
+
 Commands which normally take `--source` or `--dest` get a sensible default if
 left unspecified. `fluxengine read ibm` on its own will read drive 0 and
 write an `ibm.img` file.

+## Visualisation
+
+When doing a read (either from a real disk or from a flux file) you can use
+`--write-svg=output.svg` to write out a graphical visualisation of where the
+sectors are on the disk. Here's a IBM PC 1232kB disk:
+
+![A disk visualisation](./visualiser.svg)
+
+Blue represents data, light blue a header, and red is a bad sector. Side zero
+is on the left and side one is on the right.
+
+The visualiser is extremely primitive and you have to explicitly tell it how
+big your disk is, in milliseconds. The default is 200ms (for a normal 3.5"
+disk). For a 5.25" disk, use `--visualiser-period=166`.
+
 ## Extra programs

 Supplied with FluxEngine, but not part of FluxEngine, are some little tools I
@@ -232,25 +264,24 @@ wrote to do useful things. These are built alongside FluxEngine.

  - `brother120tool`: extracts files from a 120kB Brother filesystem image.

-  - `cwftoflux`: converts (one flavour of) CatWeasel flux file into a
-    FluxEngine flux file.
-
 ## The recommended workflow

-So you've just received, say, a huge pile of old Brother word processor disks containing valuable historical data, and you want to read them.
+So you've just received, say, a huge pile of old Brother word processor disks
+containing valuable historical data, and you want to read them.

 Typically I do this:

 ```
-$ fluxengine read brother -s :d=0 -o brother.img --write-flux=brother.flux
+$ fluxengine read brother -s :d=0 -o brother.img --write-flux=brother.flux --write-svg=brother.svg
 ```

 This will read the disk in drive 0 and write out a filesystem image. It'll
-also copy the flux to brother.flux. If I then need to tweak the settings, I
-can rerun the decode without having to physically touch the disk like this:
+also copy the flux to brother.flux and write out an SVG visualisation. If I
+then need to tweak the settings, I can rerun the decode without having to
+physically touch the disk like this:

 ```
-$ fluxengine read brother -s brother.flux -o brother.img
+$ fluxengine read brother -s brother.flux -o brother.img --write-svg=brother.svg
 ```

 Apart from being drastically faster, this avoids touching the (potentially
--- a/doc/visualiser.svg
+++ b/doc/visualiser.svg
--- a/lib/decoders/decoders.cc
+++ b/lib/decoders/decoders.cc
@@ -43,19 +43,25 @@ void AbstractDecoder::decodeToSectors(Track& track)

        recordStart = fmr.tell();
        decodeSectorRecord();
-        pushRecord(recordStart, fmr.tell());
+        Fluxmap::Position recordEnd = fmr.tell();
+        pushRecord(recordStart, recordEnd);
        if (sector.status == Sector::DATA_MISSING)
        {
            /* The data is in a separate record. */

+            sector.headerStartTime = recordStart.ns();
+            sector.headerEndTime = recordEnd.ns();
            r = advanceToNextRecord();
            if (r == DATA_RECORD)
            {
                recordStart = fmr.tell();
                decodeDataRecord();
-                pushRecord(recordStart, fmr.tell());
+                recordEnd = fmr.tell();
+                pushRecord(recordStart, recordEnd);
            }
        }
+        sector.dataStartTime = recordStart.ns();
+        sector.dataEndTime = recordEnd.ns();

        if (sector.status != Sector::MISSING)
            track.sectors.push_back(sector);
--- a/lib/flags.cc
+++ b/lib/flags.cc
@@ -29,7 +29,7 @@ void FlagGroup::addFlag(Flag* flag)
    _flags.push_back(flag);
 }

-void FlagGroup::parseFlags(int argc, const char* argv[])
+std::vector<std::string> FlagGroup::parseFlagsWithFilenames(int argc, const char* argv[])
 {
    if (_initialised)
        throw std::runtime_error("called parseFlags() twice");
@@ -66,6 +66,7 @@ void FlagGroup::parseFlags(int argc, const char* argv[])

    /* Now actually parse them. */

+    std::vector<std::string> filenames;
    int index = 1;
    while (index < argc)
    {
@@ -76,52 +77,73 @@ void FlagGroup::parseFlags(int argc, const char* argv[])
        std::string value;
        bool usesthat = false;

-        if ((thisarg.size() == 0) || (thisarg[0] != '-'))
-            Error() << "non-option parameter " << thisarg << " seen (try --help)";
-        if ((thisarg.size() > 1) && (thisarg[1] == '-'))
+        if (thisarg.size() == 0)
        {
-            /* Long option. */
-
-            auto equals = thisarg.rfind('=');
-            if (equals != std::string::npos)
-            {
-                key = thisarg.substr(0, equals);
-                value = thisarg.substr(equals+1);
-            }
-            else
-            {
-                key = thisarg;
-                value = thatarg;
-                usesthat = true;
-            }
+            /* Ignore this argument. */
+        }
+        else if (thisarg[0] != '-')
+        {
+            /* This is a filename. */
+            filenames.push_back(thisarg);
        }
        else
        {
-            /* Short option. */
+            /* This is a flag. */

-            if (thisarg.size() > 2)
+            if ((thisarg.size() > 1) && (thisarg[1] == '-'))
            {
-                key = thisarg.substr(0, 2);
-                value = thisarg.substr(2);
+                /* Long option. */
+
+                auto equals = thisarg.rfind('=');
+                if (equals != std::string::npos)
+                {
+                    key = thisarg.substr(0, equals);
+                    value = thisarg.substr(equals+1);
+                }
+                else
+                {
+                    key = thisarg;
+                    value = thatarg;
+                    usesthat = true;
+                }
            }
            else
            {
-                key = thisarg;
-                value = thatarg;
-                usesthat = true;
+                /* Short option. */
+
+                if (thisarg.size() > 2)
+                {
+                    key = thisarg.substr(0, 2);
+                    value = thisarg.substr(2);
+                }
+                else
+                {
+                    key = thisarg;
+                    value = thatarg;
+                    usesthat = true;
+                }
            }
+
+            auto flag = flags_by_name.find(key);
+            if (flag == flags_by_name.end())
+                Error() << "unknown flag '" << key << "'; try --help";
+
+            flag->second->set(value);
+            if (usesthat && flag->second->hasArgument())
+                index++;
        }

-        auto flag = flags_by_name.find(key);
-        if (flag == flags_by_name.end())
-            Error() << "unknown flag '" << key << "'; try --help";
-
-        flag->second->set(value);
-
        index++;
-        if (usesthat && flag->second->hasArgument())
-            index++;
    }
+
+    return filenames;
+}
+
+void FlagGroup::parseFlags(int argc, const char* argv[])
+{
+    auto filenames = parseFlagsWithFilenames(argc, argv);
+    if (!filenames.empty())
+        Error() << "non-option parameter " << *filenames.begin() << " seen (try --help)";
 }

 void FlagGroup::checkInitialised() const
--- a/lib/flags.h
+++ b/lib/flags.h
@@ -14,6 +14,7 @@ public:

 public:
    void parseFlags(int argc, const char* argv[]);
+    std::vector<std::string> parseFlagsWithFilenames(int argc, const char* argv[]);
    void addFlag(Flag* flag);
    void checkInitialised() const;

--- a/lib/fluxsource/streamfluxsource.cc
+++ b/lib/fluxsource/streamfluxsource.cc
@@ -24,7 +24,7 @@ public:
    void recalibrate() {}

 private:
-    const std::string& _path;
+    const std::string _path;
 };

 std::unique_ptr<FluxSource> FluxSource::createStreamFluxSource(const std::string& path)
--- a/lib/globals.h
+++ b/lib/globals.h
@@ -22,7 +22,7 @@ extern void hexdumpForSrp16(std::ostream& stream, const Bytes& bytes);
 class Error
 {
 public:
-    ~Error()
+    [[ noreturn ]] ~Error()
    {
        std::cerr << "Error: " << _stream.str() << std::endl;
        exit(1);
--- a/lib/imagereader/imagereader.cc
+++ b/lib/imagereader/imagereader.cc
@@ -7,6 +7,13 @@
 #include "imagereader/imagereader.h"
 #include "fmt/format.h"

+std::map<std::string, ImageReader::Constructor> ImageReader::formats =
+{
+	{".adf", ImageReader::createImgImageReader},
+	{".d81", ImageReader::createImgImageReader},
+	{".img", ImageReader::createImgImageReader},
+};
+
 static bool ends_with(const std::string& value, const std::string& ending)
 {
    if (ending.size() > value.size())
@@ -14,15 +21,29 @@ static bool ends_with(const std::string& value, const std::string& ending)
    return std::equal(ending.rbegin(), ending.rend(), value.rbegin());
 }

-std::unique_ptr<ImageReader> ImageReader::create(const ImageSpec& spec)
+ImageReader::Constructor ImageReader::findConstructor(const ImageSpec& spec)
 {
    const auto& filename = spec.filename;

-    if (ends_with(filename, ".img") || ends_with(filename, ".adf"))
-        return createImgImageReader(spec);
+	for (const auto& e : formats)
+	{
+		if (ends_with(filename, e.first))
+			return e.second;
+	}

-    Error() << "unrecognised image filename extension";
-    return std::unique_ptr<ImageReader>();
+	return NULL;
+}
+
+std::unique_ptr<ImageReader> ImageReader::create(const ImageSpec& spec)
+{
+    verifyImageSpec(spec);
+    return findConstructor(spec)(spec);
+}
+
+void ImageReader::verifyImageSpec(const ImageSpec& spec)
+{
+    if (!findConstructor(spec))
+        Error() << "unrecognised image filename extension";
 }

 ImageReader::ImageReader(const ImageSpec& spec):
--- a/lib/imagereader/imagereader.h
+++ b/lib/imagereader/imagereader.h
@@ -12,10 +12,21 @@ public:

 public:
    static std::unique_ptr<ImageReader> create(const ImageSpec& spec);
+	static void verifyImageSpec(const ImageSpec& spec);

 private:
+	typedef 
+		std::function<
+			std::unique_ptr<ImageReader>(const ImageSpec& spec)
+		>
+		Constructor;
+
+	static std::map<std::string, Constructor> formats;
+
    static std::unique_ptr<ImageReader> createImgImageReader(const ImageSpec& spec);

+	static Constructor findConstructor(const ImageSpec& spec);
+
 public:
 	virtual SectorSet readImage() = 0;

--- a/lib/imagewriter/imagewriter.cc
+++ b/lib/imagewriter/imagewriter.cc
@@ -7,6 +7,15 @@
 #include "imagewriter/imagewriter.h"
 #include "fmt/format.h"

+std::map<std::string, ImageWriter::Constructor> ImageWriter::formats =
+{
+	{".adf", ImageWriter::createImgImageWriter},
+	{".d64", ImageWriter::createD64ImageWriter},
+	{".d81", ImageWriter::createImgImageWriter},
+	{".img", ImageWriter::createImgImageWriter},
+	{".ldbs", ImageWriter::createLDBSImageWriter},
+};
+
 static bool ends_with(const std::string& value, const std::string& ending)
 {
    if (ending.size() > value.size())
@@ -14,19 +23,29 @@ static bool ends_with(const std::string& value, const std::string& ending)
    return std::equal(ending.rbegin(), ending.rend(), value.rbegin());
 }

-std::unique_ptr<ImageWriter> ImageWriter::create(const SectorSet& sectors, const ImageSpec& spec)
+ImageWriter::Constructor ImageWriter::findConstructor(const ImageSpec& spec)
 {
    const auto& filename = spec.filename;

-    if (ends_with(filename, ".img") || ends_with(filename, ".adf"))
-        return createImgImageWriter(sectors, spec);
-	else if (ends_with(filename, ".ldbs"))
-		return createLDBSImageWriter(sectors, spec);
-	else if (ends_with(filename, ".d64"))
-		return createD64ImageWriter(sectors, spec);
+	for (const auto& e : formats)
+	{
+		if (ends_with(filename, e.first))
+			return e.second;
+	}

-    Error() << "unrecognised image filename extension";
-    return std::unique_ptr<ImageWriter>();
+	return NULL;
+}
+
+std::unique_ptr<ImageWriter> ImageWriter::create(const SectorSet& sectors, const ImageSpec& spec)
+{
+	verifyImageSpec(spec);
+	return findConstructor(spec)(sectors, spec);
+}
+
+void ImageWriter::verifyImageSpec(const ImageSpec& spec)
+{
+	if (!findConstructor(spec))
+		Error() << "unrecognised image filename extension";
 }

 ImageWriter::ImageWriter(const SectorSet& sectors, const ImageSpec& spec):
--- a/lib/imagewriter/imagewriter.h
+++ b/lib/imagewriter/imagewriter.h
@@ -12,8 +12,17 @@ public:

 public:
    static std::unique_ptr<ImageWriter> create(const SectorSet& sectors, const ImageSpec& spec);
+	static void verifyImageSpec(const ImageSpec& filename);

 private:
+	typedef 
+		std::function<
+			std::unique_ptr<ImageWriter>(const SectorSet& sectors, const ImageSpec& spec)
+		>
+		Constructor;
+
+	static std::map<std::string, Constructor> formats;
+
    static std::unique_ptr<ImageWriter> createImgImageWriter(
 		const SectorSet& sectors, const ImageSpec& spec);
    static std::unique_ptr<ImageWriter> createLDBSImageWriter(
@@ -21,6 +30,8 @@ private:
    static std::unique_ptr<ImageWriter> createD64ImageWriter(
 		const SectorSet& sectors, const ImageSpec& spec);

+	static Constructor findConstructor(const ImageSpec& spec);
+
 public:
 	virtual void adjustGeometry();
 	void printMap();
--- a/lib/reader.cc
+++ b/lib/reader.cc
@@ -9,14 +9,16 @@
 #include "decoders/decoders.h"
 #include "sector.h"
 #include "sectorset.h"
+#include "visualiser.h"
 #include "record.h"
 #include "image.h"
 #include "bytes.h"
 #include "decoders/rawbits.h"
 #include "track.h"
+#include "imagewriter/imagewriter.h"
 #include "fmt/format.h"

-FlagGroup readerFlags { &hardwareFluxSourceFlags, &fluxmapReaderFlags };
+FlagGroup readerFlags { &hardwareFluxSourceFlags, &fluxmapReaderFlags, &visualiserFlags };

 static DataSpecFlag source(
    { "--source", "-s" },
@@ -33,6 +35,11 @@ static StringFlag destination(
    "write the raw magnetic flux to this file",
    "");

+static StringFlag visualise(
+	{ "--write-svg" },
+	"write a visualisation of the disk to this file",
+	"");
+
 static SettableFlag justRead(
 	{ "--just-read" },
 	"just read the disk and do no further processing");
@@ -142,7 +149,7 @@ static void replace_sector(std::unique_ptr<Sector>& replacing, Sector& replaceme
 			return;
 		}
 	}
-	if (!replacing || (replacing->status != Sector::OK))
+	if (!replacing || ((replacing->status != Sector::OK) && (replacement.status == Sector::OK)))
 	{
 		if (!replacing)
 			replacing.reset(new Sector);
@@ -153,7 +160,8 @@ static void replace_sector(std::unique_ptr<Sector>& replacing, Sector& replaceme
 void readDiskCommand(AbstractDecoder& decoder)
 {
 	const ImageSpec outputSpec(output);
-
+	ImageWriter::verifyImageSpec(outputSpec);
+        
 	bool failures = false;
 	SectorSet allSectors;
 	auto tracks = readTracks();
@@ -251,6 +259,9 @@ void readDiskCommand(AbstractDecoder& decoder)
        std::cout << size << " bytes decoded." << std::endl;
    }

+	if (!visualise.get().empty())
+		visualiseSectorsToFile(allSectors, visualise.get());
+
    writeSectorsToFile(allSectors, outputSpec);
 	if (failures)
 		std::cerr << "Warning: some sectors could not be decoded." << std::endl;
--- a/lib/sector.h
+++ b/lib/sector.h
@@ -27,6 +27,10 @@ public:
 	Status status = Status::INTERNAL_ERROR;
    Fluxmap::Position position;
    nanoseconds_t clock = 0;
+    nanoseconds_t headerStartTime = 0;
+    nanoseconds_t headerEndTime = 0;
+    nanoseconds_t dataStartTime = 0;
+    nanoseconds_t dataEndTime = 0;
    int physicalTrack = 0;
    int physicalSide = 0;
    int logicalTrack = 0;
--- a/lib/sectorset.h
+++ b/lib/sectorset.h
@@ -17,6 +17,9 @@ public:
 	std::unique_ptr<Sector>& get(int track, int head, int sector);
 	Sector* get(int track, int head, int sector) const;

+	const std::map<const key_t, std::unique_ptr<Sector>>& get() const
+	{ return _data; }
+
 	void calculateSize(
 		unsigned& numTracks, unsigned& numHeads, unsigned& numSectors,
 		unsigned& sectorSize) const;
--- a/lib/usb.cc
+++ b/lib/usb.cc
@@ -265,3 +265,37 @@ void usbSetDrive(int drive, bool high_density)
    await_reply<struct any_frame>(F_FRAME_SET_DRIVE_REPLY);
 }

+/* Hacky: the board always operates in little-endian mode. */
+static uint16_t read_short_from_usb(uint16_t usb)
+{
+    uint8_t* p = (uint8_t*)&usb;
+    return p[0] | (p[1] << 8);
+}
+
+static void convert_voltages_from_usb(const struct voltages& vin, struct voltages& vout)
+{
+    vout.logic0_mv = read_short_from_usb(vin.logic0_mv);
+    vout.logic1_mv = read_short_from_usb(vin.logic1_mv);
+}
+
+void usbMeasureVoltages(struct voltages_frame* voltages)
+{
+    usb_init();
+
+    struct any_frame f = {
+        { .type = F_FRAME_MEASURE_VOLTAGES_CMD, .size = sizeof(f) },
+    };
+    usb_cmd_send(&f, f.f.size);
+
+    struct voltages_frame* r = await_reply<struct voltages_frame>(F_FRAME_MEASURE_VOLTAGES_REPLY);
+    convert_voltages_from_usb(r->input_both_off, voltages->input_both_off);
+    convert_voltages_from_usb(r->input_drive_0_selected, voltages->input_drive_0_selected);
+    convert_voltages_from_usb(r->input_drive_1_selected, voltages->input_drive_1_selected);
+    convert_voltages_from_usb(r->input_drive_0_running, voltages->input_drive_0_running);
+    convert_voltages_from_usb(r->input_drive_1_running, voltages->input_drive_1_running);
+    convert_voltages_from_usb(r->output_both_off, voltages->output_both_off);
+    convert_voltages_from_usb(r->output_drive_0_selected, voltages->output_drive_0_selected);
+    convert_voltages_from_usb(r->output_drive_1_selected, voltages->output_drive_1_selected);
+    convert_voltages_from_usb(r->output_drive_0_running, voltages->output_drive_0_running);
+    convert_voltages_from_usb(r->output_drive_1_running, voltages->output_drive_1_running);
+}
--- a/lib/usb.h
+++ b/lib/usb.h
@@ -13,5 +13,6 @@ extern Bytes usbRead(int side, int revolutions);
 extern void usbWrite(int side, const Bytes& bytes);
 extern void usbErase(int side);
 extern void usbSetDrive(int drive, bool high_density);
+extern void usbMeasureVoltages(struct voltages_frame* voltages);

 #endif
--- a/lib/visualiser.cc
+++ b/lib/visualiser.cc
@@ -0,0 +1,95 @@
+#define _USE_MATH_DEFINES
+#include "globals.h"
+#include "image.h"
+#include "sector.h"
+#include "sectorset.h"
+#include "visualiser.h"
+#include "fmt/format.h"
+#include "flags.h"
+#include <iostream>
+#include <fstream>
+#include <math.h>
+
+FlagGroup visualiserFlags;
+
+static IntFlag period(
+    { "--visualiser-period" },
+    "rotational period for use by the visualiser (milliseconds)",
+    200);
+
+static const int SIZE = 480;
+static const int BORDER = 10;
+static const int RADIUS = (SIZE/2) - (BORDER/2);
+static const int CORE = 50;
+static const int TRACKS = 83;
+static const double TRACK_SPACING = double(RADIUS-CORE) / TRACKS;
+
+void visualiseSectorsToFile(const SectorSet& sectors, const std::string& filename)
+{
+    std::cout << "writing visualisation\n";
+    std::ofstream f(filename, std::ios::out);
+    if (!f.is_open())
+        Error() << "cannot open visualisation file";
+
+    f << fmt::format("<svg xmlns=\"http://www.w3.org/2000/svg\" viewBox=\"{0} {1} {2} {3}\">",
+        0, 0, SIZE*2, SIZE);
+
+    const double radians_per_ns = 2.0*M_PI / (period*1e6);
+
+    auto drawSide = [&](int side)
+    {
+        f << fmt::format("<g transform='matrix(1 0 0 -1 {} {})'>", SIZE/2 + (side*SIZE), SIZE/2);
+        f << fmt::format("<circle cx='0' cy='0' r='{}' stroke='none' fill='#ccc'/>", RADIUS);
+
+        for (int physicalTrack = 0; physicalTrack < TRACKS; physicalTrack++)
+        {
+            double radius = CORE + physicalTrack*TRACK_SPACING;
+            f << fmt::format("<circle cx='0' cy='0' r='{}' stroke='#888' stroke-width='0.5' fill='none'/>", radius);
+
+            auto drawArc = [&](const std::unique_ptr<Sector>& sector, nanoseconds_t start, nanoseconds_t end, const std::string& colour)
+            {
+                start %= period*1000000;
+                end %= period*1000000;
+                if (end < start)
+                    end += period*1000000;
+                
+                double theta1 = start * radians_per_ns;
+                double theta2 = end * radians_per_ns;
+                int large = (theta2 - theta1) >= M_PI;
+
+                f << fmt::format("\n<!-- {} {} = {} {} -->", start, end, theta1, theta2);
+                f << fmt::format("<path fill='none' stroke='{}' stroke-width='1.5' d='", colour);
+                f << fmt::format("M {} {} ", cos(theta1)*radius, sin(theta1)*radius);
+                f << fmt::format("A {0} {0} 0 {3} 1 {1} {2}", radius, cos(theta2)*radius, sin(theta2)*radius, large);
+                f << fmt::format("'><title>Track {} Head {} Sector {}; {}ms to {}ms</title></path>",
+                    sector->logicalTrack, sector->logicalSide, sector->logicalSector,
+                    start/1e6, end/1e6);
+            };
+
+            /* Sadly, SectorSets aren't indexable by physical track. */
+            for (const auto& e : sectors.get())
+            {
+                const auto& sector = e.second;
+                if ((sector->physicalSide == side) && (sector->physicalTrack == physicalTrack))
+                {
+                    const char* colour = "#f00";
+                    if (sector->status == Sector::OK)
+                        colour = "#00f";
+                    if (sector->headerStartTime && sector->headerEndTime)
+                        drawArc(sector, sector->headerStartTime, sector->headerEndTime, "#0ff");
+                    if (sector->dataStartTime && sector->dataEndTime)
+                        drawArc(sector, sector->dataStartTime, sector->dataEndTime, colour);
+                }
+            }
+        }
+
+        f << "</g>";
+    };
+
+    f << fmt::format("<rect x='0' y='0' width='{}' height='{}' stroke='none' fill='#fff'/>", SIZE*2, SIZE);
+
+    drawSide(0);
+    drawSide(1);
+
+    f << "</svg>";
+}
--- a/lib/visualiser.h
+++ b/lib/visualiser.h
@@ -0,0 +1,12 @@
+#ifndef VISUALISER_H
+#define VISUALISER_H
+
+#include "flags.h"
+
+class SectorSet;
+
+extern FlagGroup visualiserFlags;
+
+extern void visualiseSectorsToFile(const SectorSet& sectors, const std::string& filename);
+
+#endif
--- a/mkninja.sh
+++ b/mkninja.sh
@@ -183,12 +183,14 @@ buildlibrary libbackend.a \
    lib/sectorset.cc \
    lib/sql.cc \
    lib/usb.cc \
+    lib/visualiser.cc \
    lib/writer.cc \

 buildlibrary libfrontend.a \
    src/fe-cwftoflux.cc \
    src/fe-erase.cc \
    src/fe-fluxtoau.cc \
+    src/fe-fluxtoscp.cc \
    src/fe-fluxtovcd.cc \
    src/fe-inspect.cc \
    src/fe-readadfs.cc \
@@ -207,8 +209,10 @@ buildlibrary libfrontend.a \
    src/fe-readvictor9k.cc \
    src/fe-readzilogmcz.cc \
    src/fe-rpm.cc \
+    src/fe-scptoflux.cc \
    src/fe-seek.cc \
    src/fe-testbulktransport.cc \
+    src/fe-testvoltages.cc \
    src/fe-upgradefluxfile.cc \
    src/fe-writebrother.cc \
    src/fe-writeflux.cc \
@@ -230,6 +234,13 @@ buildsimpleprogram brother120tool \
    libemu.a \
    libfmt.a \

+buildsimpleprogram brother240tool \
+	-Idep/emu \
+    tools/brother240tool.cc \
+    libbackend.a \
+    libemu.a \
+    libfmt.a \
+
 runtest bitaccumulator-test tests/bitaccumulator.cc
 runtest bytes-test          tests/bytes.cc
 runtest compression-test    tests/compression.cc
--- a/protocol.h
+++ b/protocol.h
@@ -62,6 +62,8 @@ enum
    F_FRAME_RECALIBRATE_REPLY,    /* any_frame */
    F_FRAME_SET_DRIVE_CMD,        /* setdrive_frame */
    F_FRAME_SET_DRIVE_REPLY,      /* any_frame */
+    F_FRAME_MEASURE_VOLTAGES_CMD, /* any_frame */
+    F_FRAME_MEASURE_VOLTAGES_REPLY, /* voltages_frame */
 };

 enum
@@ -146,4 +148,25 @@ struct set_drive_frame
    uint8_t drive_flags;
 };

+struct voltages
+{
+    uint16_t logic0_mv;
+    uint16_t logic1_mv;
+};
+
+struct voltages_frame
+{
+    struct frame_header f;
+    struct voltages output_both_off;
+    struct voltages output_drive_0_selected;
+    struct voltages output_drive_1_selected;
+    struct voltages output_drive_0_running;
+    struct voltages output_drive_1_running;
+    struct voltages input_both_off;
+    struct voltages input_drive_0_selected;
+    struct voltages input_drive_1_selected;
+    struct voltages input_drive_0_running;
+    struct voltages input_drive_1_running;
+};
+
 #endif
--- a/src/fe-erase.cc
+++ b/src/fe-erase.cc
@@ -3,7 +3,7 @@
 #include "fluxmap.h"
 #include "writer.h"

-static FlagGroup flags;
+static FlagGroup flags { &writerFlags };

 int mainErase(int argc, const char* argv[])
 {
--- a/src/fe-fluxtoscp.cc
+++ b/src/fe-fluxtoscp.cc
@@ -0,0 +1,188 @@
+#include "globals.h"
+#include "flags.h"
+#include "fluxmap.h"
+#include "sql.h"
+#include "bytes.h"
+#include "protocol.h"
+#include "dataspec.h"
+#include "fmt/format.h"
+#include "decoders/fluxmapreader.h"
+#include "scp.h"
+#include <fstream>
+#include <algorithm>
+
+static FlagGroup flags { };
+
+static SettableFlag fortyTrackMode(
+    { "--48", "-4" },
+    "set 48 tpi mode; only every other physical track is emitted"
+);
+
+static SettableFlag singleSided(
+    { "--single-sided", "-s" },
+    "only emit side 0"
+);
+
+static IntFlag diskType(
+    { "--disk-type" },
+    "sets the SCP disk type byte",
+    0xff
+);
+
+static sqlite3* inputDb;
+
+static void syntax()
+{
+    std::cout << "Syntax: fluxengine convert fluxtoscp <fluxfile> <scpfile>\n";
+    exit(0);
+}
+
+static void write_le32(uint8_t dest[4], uint32_t v)
+{
+    dest[0] = v;
+    dest[1] = v >> 8;
+    dest[2] = v >> 16;
+    dest[3] = v >> 24;
+}
+
+static int strackno(int track, int side)
+{
+    if (fortyTrackMode)
+        track /= 2;
+    if (singleSided)
+        return track;
+    else
+        return (track << 1) | side;
+}
+
+int mainConvertFluxToScp(int argc, const char* argv[])
+{
+    auto filenames = flags.parseFlagsWithFilenames(argc, argv);
+    if (filenames.size() != 2)
+        syntax();
+
+    inputDb = sqlOpen(filenames[0], SQLITE_OPEN_READONLY);
+    auto tracks = sqlFindFlux(inputDb);
+
+    int maxTrack = 0;
+    int maxSide = 0;
+    for (auto p : tracks)
+    {
+        if (singleSided && (p.second == 1))
+            continue;
+        maxTrack = std::max(maxTrack, (int)p.first);
+        maxSide = std::max(maxSide, (int)p.second);
+    }
+    int maxStrack = strackno(maxTrack, maxSide);
+
+    std::cout << fmt::format("Writing {} {} SCP file containing {} SCP tracks\n",
+        fortyTrackMode ? "48 tpi" : "96 tpi",
+        singleSided ? "single sided" : "double sided",
+        maxStrack + 1
+    );
+
+    ScpHeader fileheader = {0};
+    fileheader.file_id[0] = 'S';
+    fileheader.file_id[1] = 'C';
+    fileheader.file_id[2] = 'P';
+    fileheader.file_id[3] = 0x18; /* Version 1.8 of the spec */
+    fileheader.type = diskType;
+    fileheader.revolutions = 5;
+    fileheader.start_track = 0;
+    fileheader.end_track = maxStrack;
+    fileheader.flags = SCP_FLAG_INDEXED | (fortyTrackMode ? 0 : SCP_FLAG_96TPI);
+    fileheader.cell_width = 0;
+    fileheader.heads = singleSided ? 1 : 0;
+
+    Bytes trackdata;
+    ByteWriter trackdataWriter(trackdata);
+
+    int trackstep = 1 + fortyTrackMode;
+    int maxside = singleSided ? 0 : 1;
+    for (int track = 0; track <= maxTrack; track += trackstep)
+    {
+        for (int side = 0; side <= maxside; side++)
+        {
+            int strack = strackno(track, side);
+            std::cout << fmt::format("FE track {}.{}, SCP track {}: ", track, side, strack) << std::flush;
+
+            auto fluxmap = sqlReadFlux(inputDb, track, side);
+            ScpTrack trackheader = {0};
+            trackheader.track_id[0] = 'T';
+            trackheader.track_id[1] = 'R';
+            trackheader.track_id[2] = 'K';
+            trackheader.strack = strack;
+
+            FluxmapReader fmr(*fluxmap);
+            Bytes fluxdata;
+            ByteWriter fluxdataWriter(fluxdata);
+
+            int revolution = 0;
+            unsigned revTicks = 0;
+            unsigned totalTicks = 0;
+            unsigned ticksSinceLastPulse = 0;
+            uint32_t startOffset = 0;
+            while (revolution < 5)
+            {
+                unsigned ticks;
+                int opcode = fmr.readOpcode(ticks);
+                if (ticks)
+                {
+                    ticksSinceLastPulse += ticks;
+                    totalTicks += ticks;
+                    revTicks += ticks;
+                }
+
+                switch (opcode)
+                {
+                    case -1: /* end of flux, treat like an index marker */
+                    case F_OP_INDEX:
+                    {
+                        auto* revheader = &trackheader.revolution[revolution];
+                        write_le32(revheader->offset, startOffset + sizeof(ScpTrack));
+                        write_le32(revheader->length, (fluxdataWriter.pos - startOffset) / 2);
+                        write_le32(revheader->index, revTicks * NS_PER_TICK / 25);
+                        revolution++;
+                        revheader++;
+                        revTicks = 0;
+                        startOffset = fluxdataWriter.pos;
+                        break;
+                    }
+
+                    case F_OP_PULSE:
+                    {
+                        unsigned t = ticksSinceLastPulse * NS_PER_TICK / 25;
+                        while (t >= 0x10000)
+                        {
+                            fluxdataWriter.write_be16(0);
+                            t -= 0x10000;
+                        }
+                        fluxdataWriter.write_be16(t);
+                        ticksSinceLastPulse = 0;
+                        break;
+                    }
+                }
+            }
+
+            write_le32(fileheader.track[strack], trackdataWriter.pos + sizeof(ScpHeader));
+            trackdataWriter += Bytes((uint8_t*)&trackheader, sizeof(trackheader));
+            trackdataWriter += fluxdata;
+
+            std::cout << fmt::format("{} ms in {} bytes\n",
+                totalTicks * MS_PER_TICK,
+                fluxdata.size());
+        }
+    }
+
+    sqlClose(inputDb);
+    
+    std::cout << "Writing output file...\n";
+    std::ofstream of(filenames[1], std::ios::out | std::ios::binary);
+    if (!of.is_open())
+        Error() << "cannot open output file";
+    of.write((const char*) &fileheader, sizeof(fileheader));
+    of.write((const char*) trackdata.begin(), trackdata.size());
+    of.close();
+
+    return 0;
+}
--- a/src/fe-readibm.cc
+++ b/src/fe-readibm.cc
@@ -17,13 +17,18 @@ static IntFlag sectorIdBase(
 	"Sector ID of the first sector.",
 	1);

+static BoolFlag ignoreSideByte(
+	{ "--ignore-side-byte" },
+	"Ignore the side byte in the sector ID, and use the physical side instead.",
+	false);
+
 int mainReadIBM(int argc, const char* argv[])
 {
 	setReaderDefaultSource(":t=0-79:s=0-1");
 	setReaderDefaultOutput("ibm.img");
    flags.parseFlags(argc, argv);

-	IbmDecoder decoder(sectorIdBase);
+	IbmDecoder decoder(sectorIdBase, ignoreSideByte);
 	readDiskCommand(decoder);
    return 0;
 }
--- a/src/fe-readmx.cc
+++ b/src/fe-readmx.cc
@@ -8,7 +8,6 @@
 #include "sector.h"
 #include "sectorset.h"
 #include "record.h"
-#include <fmt/format.h>

 static FlagGroup flags { &readerFlags };

--- a/src/fe-rpm.cc
+++ b/src/fe-rpm.cc
@@ -8,7 +8,7 @@ static FlagGroup flags;
 static DataSpecFlag source(
    { "--source", "-s" },
    "source for data",
-    ":d=0");
+    ":d=0:t=0:s=0");

 int mainRpm(int argc, const char* argv[])
 {
--- a/src/fe-scptoflux.cc
+++ b/src/fe-scptoflux.cc
@@ -0,0 +1,142 @@
+#include "globals.h"
+#include "fluxmap.h"
+#include "sql.h"
+#include "bytes.h"
+#include "protocol.h"
+#include "fmt/format.h"
+#include "scp.h"
+#include <fstream>
+
+static std::ifstream inputFile;
+static sqlite3* outputDb;
+static ScpHeader header;
+static nanoseconds_t resolution;
+static int startSide;
+static int endSide;
+
+static void syntax()
+{
+    std::cout << "Syntax: fluxengine convert cwftoflux <cwffile> <fluxfile>\n";
+    exit(0);
+}
+
+static void check_for_error()
+{
+    if (inputFile.fail())
+        Error() << fmt::format("I/O error: {}", strerror(errno));
+}
+
+static int trackno(int strack)
+{
+    if (startSide == endSide)
+        return strack;
+    return strack >> 1;
+}
+
+static int headno(int strack)
+{
+    if (startSide == endSide)
+        return startSide;
+    return strack & 1;
+}
+
+static void read_header()
+{
+    inputFile.read((char*) &header, sizeof(header));
+    check_for_error();
+
+    if ((header.file_id[0] != 'S')
+            || (header.file_id[1] != 'C')
+            || (header.file_id[2] != 'P'))
+        Error() << "input not a SCP file";
+
+    resolution = 25 * (header.resolution + 1);
+    startSide = (header.heads == 2) ? 1 : 0;
+    endSide = (header.heads == 1) ? 0 : 1;
+
+    if ((header.cell_width != 0) && (header.cell_width != 16))
+        Error() << "currently only 16-bit cells are supported";
+
+    std::cout << fmt::format("tracks {}-{}, heads {}-{}\n",
+        trackno(header.start_track), trackno(header.end_track), startSide, endSide);
+    std::cout << fmt::format("sample resolution: {} ns\n", resolution);
+}
+
+static void read_track(int strack)
+{
+    uint32_t offset = Bytes(header.track[strack], 4).reader().read_le32();
+
+    ScpTrack trackheader;
+    inputFile.seekg(offset, std::ios::beg);
+    inputFile.read((char*) &trackheader, sizeof(trackheader));
+    check_for_error();
+
+    if ((trackheader.track_id[0] != 'T')
+            || (trackheader.track_id[1] != 'R')
+            || (trackheader.track_id[2] != 'K'))
+        Error() << "corrupt SCP file";
+
+    std::cout << fmt::format("{}.{}: ", trackno(strack), headno(strack))
+        << std::flush;
+
+    Fluxmap fluxmap;
+    nanoseconds_t pending = 0;
+    unsigned inputBytes = 0;
+    for (int revolution = 0; revolution < header.revolutions; revolution++)
+    {
+        if (revolution != 0)
+            fluxmap.appendIndex();
+
+        uint32_t datalength = Bytes(trackheader.revolution[revolution].length, 4).reader().read_le32();
+        uint32_t dataoffset = Bytes(trackheader.revolution[revolution].offset, 4).reader().read_le32();
+
+        Bytes data(datalength*2);
+        inputFile.seekg(dataoffset + offset, std::ios::beg);
+        inputFile.read((char*) data.begin(), data.size());
+        check_for_error();
+
+        ByteReader br(data);
+        for (int cell = 0; cell < datalength; cell++)
+        {
+            uint16_t interval = br.read_be16();
+            if (interval)
+            {
+                fluxmap.appendInterval((interval + pending) * resolution / NS_PER_TICK);
+                fluxmap.appendPulse();
+                pending = 0;
+            }
+            else
+                pending += 0x10000;
+        }
+
+        inputBytes += datalength*2;
+    }
+
+    std::cout << fmt::format(" {} ms in {} input bytes and {} output bytes\n",
+        fluxmap.duration() / 1e6, inputBytes, fluxmap.bytes());
+    sqlWriteFlux(outputDb, trackno(strack), headno(strack), fluxmap);
+}
+
+int mainConvertScpToFlux(int argc, const char* argv[])
+{
+    if (argc != 3)
+        syntax();
+    
+    inputFile.open(argv[1], std::ios::in | std::ios::binary);
+    if (!inputFile.is_open())
+		Error() << fmt::format("cannot open input file '{}'", argv[1]);
+
+    outputDb = sqlOpen(argv[2], SQLITE_OPEN_READWRITE | SQLITE_OPEN_CREATE);
+    sqlPrepareFlux(outputDb);
+    sqlWriteIntProperty(outputDb, "version", FLUX_VERSION_CURRENT);
+    sqlStmt(outputDb, "BEGIN;");
+
+    read_header();
+    inputFile.seekg(sizeof(header), std::ios::beg);
+    for (unsigned i=header.start_track; i<=header.end_track; i++)
+        read_track(i);
+
+    sqlStmt(outputDb, "COMMIT;");
+    sqlClose(outputDb);
+    return 0;
+}
--- a/src/fe-testvoltages.cc
+++ b/src/fe-testvoltages.cc
@@ -0,0 +1,47 @@
+#include "globals.h"
+#include "flags.h"
+#include "usb.h"
+#include "protocol.h"
+#include <fmt/format.h>
+
+static FlagGroup flags;
+
+static std::string display_voltages(struct voltages& v)
+{
+    return fmt::format(
+        "      Logic 1 / 0:  {:.2f}V / {:.2f}V\n",
+        v.logic0_mv / 1000.0,
+        v.logic1_mv / 1000.0);
+}
+
+int mainTestVoltages(int argc, const char* argv[])
+{
+    flags.parseFlags(argc, argv);
+    struct voltages_frame f;
+    usbMeasureVoltages(&f);
+
+    std::cout << "Output voltages:\n"
+              << "  Both drives deselected\n"
+              << display_voltages(f.output_both_off)
+              << "  Drive 0 selected\n"
+              << display_voltages(f.output_drive_0_selected)
+              << "  Drive 1 selected\n"
+              << display_voltages(f.output_drive_1_selected)
+              << "  Drive 0 running\n"
+              << display_voltages(f.output_drive_0_running)
+              << "  Drive 1 running\n"
+              << display_voltages(f.output_drive_1_running)
+              << "Input voltages:\n"
+              << "  Both drives deselected\n"
+              << display_voltages(f.input_both_off)
+              << "  Drive 0 selected\n"
+              << display_voltages(f.input_drive_0_selected)
+              << "  Drive 1 selected\n"
+              << display_voltages(f.input_drive_1_selected)
+              << "  Drive 0 running\n"
+              << display_voltages(f.input_drive_0_running)
+              << "  Drive 1 running\n"
+              << display_voltages(f.input_drive_1_running);
+
+    return 0;
+}
--- a/src/fluxengine.cc
+++ b/src/fluxengine.cc
@@ -5,7 +5,9 @@ typedef int command_cb(int agrc, const char* argv[]);
 extern command_cb mainErase;
 extern command_cb mainConvertCwfToFlux;
 extern command_cb mainConvertFluxToAu;
+extern command_cb mainConvertFluxToScp;
 extern command_cb mainConvertFluxToVcd;
+extern command_cb mainConvertScpToFlux;
 extern command_cb mainInspect;
 extern command_cb mainReadADFS;
 extern command_cb mainReadAESLanier;
@@ -25,6 +27,7 @@ extern command_cb mainReadZilogMCZ;
 extern command_cb mainRpm;
 extern command_cb mainSeek;
 extern command_cb mainTestBulkTransport;
+extern command_cb mainTestVoltages;
 extern command_cb mainUpgradeFluxFile;
 extern command_cb mainWriteBrother;
 extern command_cb mainWriteFlux;
@@ -40,6 +43,7 @@ struct Command
 static command_cb mainRead;
 static command_cb mainWrite;
 static command_cb mainConvert;
+static command_cb mainTest;

 static std::vector<Command> commands =
 {
@@ -49,7 +53,7 @@ static std::vector<Command> commands =
    { "read",              mainRead,              "Reads a disk, producing a sector image.", },
    { "rpm",               mainRpm,               "Measures the disk rotational speed.", },
    { "seek",              mainSeek,              "Moves the disk head.", },
-    { "testbulktransport", mainTestBulkTransport, "Measures your USB bandwidth.", },
+    { "test",              mainTest,              "Various testing commands.", },
    { "upgradefluxfile",   mainUpgradeFluxFile,   "Upgrades a flux file from a previous version of this software.", },
    { "write",             mainWrite,             "Writes a sector image to a disk.", },
    { "writeflux",         mainWriteFlux,         "Writes a raw flux file. Warning: you can't use this to copy disks.", },
@@ -83,10 +87,18 @@ static std::vector<Command> writeables =
 static std::vector<Command> convertables =
 {
    { "cwftoflux",     mainConvertCwfToFlux, "Converts CatWeasel stream files to flux.", },
+    { "scptoflux",     mainConvertScpToFlux, "Converts Supercard Pro stream files to flux.", },
    { "fluxtoau",      mainConvertFluxToAu,  "Converts (one track of a) flux file to an .au audio file.", },
+    { "fluxtoscp",     mainConvertFluxToScp, "Converrt a flux file to a Supercard Pro file.", },
    { "fluxtovcd",     mainConvertFluxToVcd, "Converts (one track of a) flux file to a VCD file.", },
 };

+static std::vector<Command> testables =
+{
+    { "bulktransport", mainTestBulkTransport, "Measures your USB bandwidth.", },
+    { "voltages",      mainTestVoltages,      "Measures the FDD bus voltages.", },
+};
+
 static void extendedHelp(std::vector<Command>& subcommands, const std::string& command)
 {
    std::cout << "fluxengine: syntax: fluxengine " << command << " <format> [<flags>...]\n"
@@ -127,6 +139,9 @@ static int mainWrite(int argc, const char* argv[])
 static int mainConvert(int argc, const char* argv[])
 { return mainExtended(convertables, "convert", argc, argv); }

+static int mainTest(int argc, const char* argv[])
+{ return mainExtended(testables, "test", argc, argv); }
+
 static void help()
 {
    std::cout << "fluxengine: syntax: fluxengine <command> [<flags>...]\n"
--- a/src/scp.h
+++ b/src/scp.h
@@ -0,0 +1,43 @@
+#ifndef SCP_H
+#define SCP_H
+
+struct ScpHeader
+{
+    char file_id[3];       // file ID - 'SCP'
+    uint8_t version;       // major/minor in nibbles
+    uint8_t type;          // disk type - subclass/class in nibbles
+    uint8_t revolutions;   // up to 5
+    uint8_t start_track;   // 0..165
+    uint8_t end_track;     // 0..165
+    uint8_t flags;         // see below
+    uint8_t cell_width;    // in bits, 0 meaning 16
+    uint8_t heads;         // 0 = both, 1 = side 0 only, 2 = side 1 only
+    uint8_t resolution;    // 25ns * (resolution+1)
+    uint8_t checksum[4];   // of data after this point
+    uint8_t track[165][4]; // track offsets, not necessarily 165
+};
+
+enum
+{
+    SCP_FLAG_INDEXED    = (1<<0),
+    SCP_FLAG_96TPI      = (1<<1),
+    SCP_FLAG_360RPM     = (1<<2),
+    SCP_FLAG_NORMALIZED = (1<<3),
+    SCP_FLAG_READWRITE  = (1<<4),
+    SCP_FLAG_FOOTER     = (1<<5)
+};
+
+struct ScpTrack
+{
+    char track_id[3];      // 'TRK'
+    uint8_t strack;        // SCP track number
+    struct
+    {
+        uint8_t index[4];  // time for one revolution
+        uint8_t length[4]; // number of bitcells
+        uint8_t offset[4]; // offset to bitcell data, relative to track header
+    }
+    revolution[5];
+};
+
+#endif
--- a/tools/brother240tool.cc
+++ b/tools/brother240tool.cc
@@ -0,0 +1,56 @@
+#include "globals.h"
+#include "fmt/format.h"
+#include <fstream>
+
+static std::fstream inputFile;
+
+void syntax()
+{
+    std::cout << "Syntax: brother240tool <image>\n"
+                 "The disk image will be flipped from Brother to DOS format and back\n"
+                 "again.\n";
+    exit(0);
+}
+
+uint8_t getbyte(uint32_t offset)
+{
+    inputFile.seekg(offset, std::ifstream::beg);
+    return inputFile.get();
+}
+
+void putbyte(uint32_t offset, uint8_t value)
+{
+    inputFile.seekp(offset, std::ifstream::beg);
+    inputFile.put(value);
+}
+
+int main(int argc, const char* argv[])
+{
+    if (argc < 2)
+        syntax();
+    
+    inputFile.open(argv[1], std::ios::in | std::ios::out | std::ios::binary);
+    if (!inputFile.is_open())
+		Error() << fmt::format("cannot open input file '{}'", argv[1]);
+
+    uint8_t b1 = getbyte(0x015);
+    uint8_t b2 = getbyte(0x100);
+    if ((b1 == 0x58) && (b2 == 0x58))
+    {
+        std::cerr << "Flipping from Brother to DOS.\n";
+        putbyte(0x015, 0xf0);
+        putbyte(0x100, 0xf0);
+    }
+    else if ((b1 == 0xf0) && (b2 == 0xf0))
+    {
+        std::cerr << "Flipping from DOS to Brother.\n";
+        putbyte(0x015, 0x58);
+        putbyte(0x100, 0x58);
+    }
+    else
+        Error() << "Unknown image format.";
+
+    inputFile.close();
+    return 0;
+}
+
Author	SHA1	Message	Date
David Given	ed0d578b18	Merge pull request #114 from davidgiven/fixing1 Add support for measuring signal line voltages.	2019-12-11 00:28:13 +01:00
David Given	32bb956710	Detect voltage levels correctly.	2019-12-11 00:05:34 +01:00
David Given	f436d6b582	Add a feature where we can measure the FDD bus signal voltages using the PSoC's ADCs. Increase the track step pulse width to 6us, because.	2019-12-10 22:36:18 +01:00
David Given	8ee6eed4dc	Merge pull request #112 from davidgiven/fixing Rework the sequencer completely, because bizarrely writing disks just stopped working	2019-11-29 22:02:44 +01:00
David Given	3094c5c919	Add missing files.	2019-11-29 18:49:22 +01:00
David Given	1e012699af	Clean up the Verilog a bit.	2019-11-25 20:54:13 +01:00
David Given	91d6e9aeb9	Rewrite the sequencer engine with a separate fifo component and a pure verilog sequencer --- much easier to understand. We can write disks again!	2019-11-25 20:52:13 +01:00
David Given	a40b26ff46	Archival checkin for trying to figure out why writes no longer work.	2019-11-24 15:14:32 +01:00
David Given	ebcb9c4bb0	Switch the output lines to open-drain drive low.	2019-11-24 02:06:45 +01:00
David Given	2520834b18	Add the brother240tool program.	2019-11-24 01:46:02 +01:00
David Given	a1f3087046	Add an 8" drive datasheet.	2019-11-24 01:45:43 +01:00
David Given	e9670e205e	Don't erroneously crash out if the t and s parameters are omitted from the rpm command.	2019-10-14 22:25:43 +02:00
David Given	658e2b7295	Properly initialise flags. Fixes: #109	2019-09-22 21:55:37 +02:00
David Given	7b4a8d6de2	Merge pull request #108 from davidgiven/scp Add very beta support for scp import and export	2019-09-21 22:32:52 +02:00
David Given	e8f7b51aef	Another documentation tweak.	2019-09-21 22:15:44 +02:00
David Given	9d6bc57a5f	Update documentation.	2019-08-31 12:32:52 +02:00
David Given	73766f92b4	Fix the flux to scp converter.	2019-08-31 12:31:33 +02:00
David Given	80badf3b54	Remember to check in the build file changes...	2019-08-31 12:09:11 +02:00
David Given	116529f85a	Archival, non-working checkin of the flux to scp converter (it appears to produce garbage).	2019-08-31 01:41:11 +02:00
David Given	5a2b2bc07a	Allow support for command lines with non-argument filenames.	2019-08-31 01:40:44 +02:00
David Given	41070395c0	Merge pull request #105 from davidgiven/scp Add conversion support for Supercard Pro scp files.	2019-08-28 23:52:27 +02:00
David Given	4304d1eede	Add the Supercard Pro decoder.	2019-08-28 23:32:09 +02:00
David Given	46f1b0aef4	Merge pull request #104 from davidgiven/sampler Fix a nasty sampler bug leading to corrupted data	2019-08-28 00:23:21 +02:00
David Given	9923d67a7c	Merge pull request #103 from davidgiven/visualiser Add a simple disk visualiser.	2019-08-28 00:20:49 +02:00
David Given	99335a84fd	Add documentation for the visualiser.	2019-08-28 00:19:18 +02:00
David Given	c266779433	Fix a bug where index pulses where being turned into flux pulses on read, leading to completely broken data whenever an index pulse happened.	2019-08-27 23:58:07 +02:00
David Given	bdcc12cd53	Correctly import M_PI.	2019-08-27 23:08:13 +02:00
David Given	7988d0fe24	Don't replace bad sectors with more bad sectors. This means that if a sector is permanently bad, the one which wins and goes into the output SectorSet is the first one, not the last one. Frequently the last sector is truncated by the end of read and so it isn't useful.	2019-08-27 22:39:24 +02:00
David Given	27f5c294b1	The visualiser period can now be specified in a flag.	2019-08-27 01:21:49 +02:00
David Given	b9a53e0d1c	First draft of the visualiser.	2019-08-27 01:07:57 +02:00
David Given	f8b6d5e6fb	Merge.	2019-08-25 00:24:34 +02:00
David Given	04ff31c348	Add a flag to the IBM decoder to tell it to ignore the logical sector IDs (some formats don't use these).	2019-08-25 00:24:02 +02:00
David Given	77b4aebd1b	Fix crashing bug when reading Kryoflux streams.	2019-08-24 23:53:22 +02:00
David Given	4056364300	Merge pull request #99 from davidgiven/extensions Validate image extensions before reading, not after.	2019-08-22 22:09:42 +02:00
David Given	60bfe050d3	Refactor the way image extensions are handled to be generally cleaner. Add support for validating ImageSpecs before we actually want to read/write an image, so as to allow us to check the extension before wasting time reading a disk. Make .d81 an alias of .img.	2019-08-21 00:45:10 +02:00
David Given	28d0ce765e	Merge pull request #93 from davidgiven/hex Add precompiled firmware	2019-08-15 22:26:50 +02:00
David Given	4954d33307	Add documentation for using the precompiled firmware.	2019-08-15 22:19:30 +02:00
David Given	55f3354287	Add precompiled hex for the firmware.	2019-08-15 21:52:11 +02:00