Commit Graph

59 Commits

Author SHA1 Message Date
David Given
edbe624c5a Hopefully, finally, fix the hang-on-read issue. 2019-12-12 20:09:49 +01:00
David Given
44e2334815 Typo fix. Make sure that both drives get deselected when the motor stops (to
make the LEDs go out).
2019-12-12 00:17:59 +01:00
David Given
072a097003 Archival (non-functioning) checkin of Verilog-based sampler code. Sadly, we've
run into size limits for the device, and I need to slim down.
2019-12-11 22:51:27 +01:00
David Given
a66e704bab Start ripping out the awful UDB-based sampler code, replacing it with a Verilog
one and a standalone FIFO. This gets the FIFO working.
2019-12-11 21:13:57 +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
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
56a36072f7 Sampler state machine cleanup; more debugging tools for the logic analyser. 2019-07-12 21:09:53 +02:00
David Given
d1c2e2b611 Better handling of seeks (plus tracing). 2019-05-01 13:06:56 +02:00
David Given
46b48f4638 Ignore the /DSKCHG line --- it doesn't add a lot of value (it allows us to
rehome if people change disks while the motor is running) and it means that
people need to worry about whether their drive produces /DSKCHG or /READY.
2019-04-21 01:15:30 +02:00
David Given
da8cae61b7 Add a debug UART back on pin 2.0 to get some semblance of debug information off
the board. Discover a fun edge case where output transfers that were an exact
number of frames weren't being terminated correctly.
2019-04-06 17:59:23 +02:00
David Given
707563bec6 Hopefully fix the underrun issue when reading from HD disks. 2019-03-27 22:10:58 +01:00
David Given
098b2371a4 Crunched datastreams are now used when writing. 2019-03-27 21:58:41 +01:00
David Given
bcc5a5f2cd Interim but working support for crunched data streams when reading from the
device; writes haven't been converted yet. Reduces the bandiwidth from about
800kB/s to about 500kB/s, which is about what I thought.
2019-03-26 23:03:19 +01:00
David Given
0453837c03 The high-density flag now actually changes the high-density line to the drive. 2019-03-26 20:05:16 +01:00
David Given
45eaf14133 Add a flag for setting the drive to high density mode. 2019-03-23 11:32:55 +01:00
David Given
4fe27afe9f Backed out changeset cd5bed99b0b4 --- erroneously pushed to master. 2019-03-24 17:59:17 +01:00
David Given
7f9a85ff77 Add a flag for setting the drive to high density mode. 2019-03-23 11:32:55 +01:00
David Given
f20ad8368a Non-working basis of a UDB datapath based sequencer. No more clock errors. 2019-02-28 01:03:58 +01:00
David Given
864a3c0e4b Use 16-bit DMA transfers now we have a FIFO. Better CPU efficiency! 2019-02-27 23:56:17 +01:00
David Given
4b0c7b095b FINALLY make the UDB-based sampler work... although without rollover, yet.
Sadly I seem to also have broken the sequencer.
2019-02-27 23:00:47 +01:00
David Given
039d6b5fdd More fiddling with the UDB sampler. Still doesn't work. 2019-02-26 22:37:45 +01:00
David Given
d3df012468 Initialise the FIFOs. Doesn't do any good. 2019-02-25 23:52:44 +01:00
David Given
74c6c6db56 Non-working attempt at replacing the sampler with a UDB datapath (so I can use
the FIFO).
2019-02-24 14:50:33 +01:00
David Given
34a4c888b5 Rewrite the Verilog *again*, and increase the CPU clock rate --- it's now a
little more reliable at reading long intervals off disk, but does seem to be
doing it. I'm going to definitely need some better sampling logic here and
probably a FIFO. But it'll do for now.
2019-02-23 19:51:27 +01:00
David Given
753a4a21ef Rewrite the sampler Verilog to use much more consistent logic. Still doesn't
work for long intervals, though.
2019-02-23 12:42:42 +01:00
David Given
970668aca5 Non-working attempt to replace the playback logic with Verilog. 2019-02-22 21:26:54 +01:00
David Given
a77925fe64 Replace the complicated sampler with 10 lines of Verilog; the hardware should
now be able to handle any length of transition. And it's simpler.
2019-02-22 20:01:34 +01:00
David Given
2527ac2ce9 Initial support for twin drives and 5.25" drives. 2019-02-11 23:43:44 +01:00
David Given
65315f4603 Take out the UART --- it's too much hassle. 2019-02-09 23:02:05 +01:00
David Given
9f64de0c49 Do a recalibrate when retrying a track read --- it makes things a bit more
reliable.
2019-02-09 22:55:46 +01:00
David Given
80cb1e7a81 Add the ability to erase tracks. The writer now erases tracks for which no data
is available.
2019-01-10 23:51:47 +01:00
David Given
f9146b2b92 You can now record multiple revolutions (necessary for the Brother which puts
the index hole in the wrong place). Sector header record GCR is solved,
probably; data record GCR is partially solved, although kinda weird (should
check that my pulse train decoder isn't dropping bits).
2018-10-19 02:11:38 +02:00
David Given
e6a424d17a Abruptly realise that the capture logic was completely missing transitions too
big to time; so, redesign it. Now the longest transition is 0xfe ticks and a
pulse is inserted if it's too long. Capture is way more robust now and the
resulting pulsetrain is a solid 198ms; and I wrote my first readable disk! (A
PC HD disk. Sadly, writing to the Brother didn't work.)
2018-10-17 00:26:33 +02:00
David Given
99e222d012 Change the record mechanism to use an upcounter, not a timer. 2018-10-13 16:54:51 +02:00
David Given
aa7d420754 Start work on an autocalibrator to detect precompensation, but something's gone
wrong and our reads are all bunk.
2018-10-13 12:04:37 +02:00
David Given
b46d55cc07 The USB capture/replay interface now uses timestamps rather than intervals;
this makes the hardware considerably simpler and more reliable (as I don't need
to spend time resetting the timers between pulses). Still doesn't help writes,
though. Simplify and improve clock detection; add an abortive attempt at an FM
decoder (turns out that the Brother doesn't use FM).
2018-10-13 01:19:17 +02:00
David Given
40b9fbc25d Fix ghastly DMA ordering bug leading to corrupted writes. Writes are less
corrupted! Still can't reliably read back what I wrote, though. Added a test
pattern feature to write, to aid debugging.
2018-10-09 00:23:21 +02:00
David Given
443082f3c4 Written my first data --- it's kinda garbled, but there's definitely sectors in
there!
2018-10-06 23:30:14 +02:00
David Given
30271d7e95 Just enough writing works to utterly destroy tracks now. 2018-10-06 23:01:24 +02:00
David Given
8f1cef48b1 Realise that the weird data dropouts were due to a stray capacitor on the
board... so remove it. Better now. Also realise that PSoC Creator lies to you
about clocks, so adjust the sample clock to be derivable from the USB clock,
making it both the right frequency and much more accurate --- decode success is
dramatically improved (presumably due to less jitter). Redesign the capture
logic to use a timer; simpler now.
2018-10-06 18:32:57 +02:00
David Given
74d051dff3 Start sketching out the write code; attempt to make more robust in the face of
the weird data dropouts.
2018-10-06 13:47:34 +02:00
David Given
d6b71beacf Reduced the sampling rate to 8MHz; 16MHz means that on a 720kB disk some
samples are more than 128 ticks apart! Doubled the settling time to make reads
more reliable; added disk change logic to rehome the disk when you replace
floppies.
2018-10-05 22:58:56 +02:00
David Given
339cdd5105 Add a partially working MFM decoder --- MFM's fine, it's aligning to sync bytes
which is hard.
2018-10-04 00:02:13 +02:00
David Given
fccabb3266 Add back in the hacky output file, for testing; replace the capture logic with
an upcounter, and replace the pulse-in-high-bit stuff.
2018-10-03 19:45:27 +02:00
David Given
841c1ed516 Attempt to capture rollover events --- don't think it works. Add a basic
command processor.
2018-10-02 23:03:07 +02:00
David Given
913829afbb Discover timers; drastically simplify and betterify everything. 2018-10-02 00:17:37 +02:00
David Given
51cb1ae785 We just read our first floppy! Turns out the secret is to, once again, remove
C7 from the board as it's preventing the READ DATA line showing anything.
2018-10-01 23:30:51 +02:00
David Given
4e19882d76 Archival checkin of messed-about non-working code to actually read data from
disk. Something's wrong with the DMA; requesting a transfer every 2us with a TD
size of 64 bytes is somehow leading to an nrq interrupt every 8us. Mysterious.
2018-09-30 01:13:39 +02:00