started working on proper README

README.md

@@ -1,122 +1,46 @@
-M8Q time calibration
+# exixe: Low-cost miniature driver module for Nixie tubes
 
-ws2812 underlight
+![Alt text](https://i.imgur.com/JjhNDUQ.jpg)
 
-tempture sensor
+![Alt text](https://i.imgur.com/I1maqhw.jpg)
 
-8 tubes, in-14
+exixe is a driver module for IN-12 and IN-14 Nixie tubes, I developed them while building my own Nixie clock. 
 
-MM DD HH mm
+## Features
 
-HH mm SS temp
+Compared to the traditional approach, exixe board offers significant advantages:
 
-3D printing?
+#### Small and modular
+* 2x4 cm (0.79x1.57 inches)
+* Breadboard friendly
+* Easy integration
 
-guardian theme?
+#### Low-cost
+* $3 in components
+* No need for obscure vintage driver chips
 
-bluetooth
+#### SPI interface
+* High speed, up to 8MHz SCLK
+* Available on virtually all embedded systems including Arduino and Raspberry Pi
+* Simple 16-byte command packet
 
-eeprom
+#### Advanced control
+* Powered by STM32
+* Hardware PWM on all cathodes for silky smooth dimming and animations
+* Overdrive feature for poisoned cathodes
 
-light senser
+#### RGB backlit
+* ...well because RGB
 
-stm32f042K 14 PWM channels!
+## Technical details
 
-SPI 3MHz MAX, 16 byte command
+tube needs...
 
-USB C connector
+over drive...
 
-disable boot0 in option byte 
-SWD cross talk in jumper wire
 
-rg 470ohm
-b 0ohm
+stm32f042k6t6, 32 pin, enough pin... timer pwm channels
 
-htim14.Instance->CCR1 = pwm_value;
-pwm_value must be smaller than counter period
+## SPI command protocol
 
-3528 rgb led
-
-http://www.mouser.co.uk/ProductDetail/Wurth-Electronics/150141M173100/?qs=sGAEpiMZZMuCm2JlHBGeflo8zLeA%2ffbJXCK04oeb2W5E0T0m7VNM2Q%3d%3d
-
-48MHz sysclock
-Prescaler 1920
-period 127
-194Hz
-
-0		0xab
-1		1
-2		2
-3		3
-4		4
-5		5
-6		6
-7		7
-8		8
-9		9
-10		0
-11		left dot
-12		right dot
-13		red
-14		green
-15		blue
-
-up to 20MHZ
-
-Thanks to this diode, when an EMC stress oc
-curs, the level of the noise is clamped to V
-DD
-. 
-As a consequence, channels implemented on FT I/O show a better noise immunity
-
-ref-packages
-
-find smt 8MHz and 32.768KHz crystals
-
-remove tx rx header put backing transistors there
-
-remove eeprom 
-put pf0 pf1 tx rx on test points
-
-change drc will change pad size
-
-eixie reset after a short delay when invalid header
-gps fix led
-
-polygon rank higher will isolate lower
-
-use driven shield, no ground or signal underneath
-
-test reversed tx rx
-
-test rtos
-
-looks like reset is needed for correct SPI snyc
-
-current state, 16 bytes,
-new state, 16 bytes
-compare difference between the two, then do fade animation
-send animation SPI updates 60fps
-
-animation is active if animation_frame_end is bigger than current frame counter
-
-animation type
-0: fade to black then fade into another digit
-1: 2 digits crossfade
-
-2 frame arrays, start digit brightness, end digit brightness
-
-en pin on power supply normally off connected to a gpio?
-
-PA8 PA9 PA10 is messed up fix them in the next revision
-
-heat shrink tube for LED cover
-
-PC13 seems to be damanged by 1wire, use it for GPS reset
-
-ZDA – Time and Date 
-UTC, day, month, year and local time zone
-
-add IWDG
-
-looks like I don't need baking function for new IN-12, keep a jumper though
+exixe expects a fixed 16-byte command, which should be

resources/old_readme.txt

@@ -0,0 +1,14 @@
+
+
+exixe module and clock board:
+
+GPS calibrated clock @ nanosecond accruacy
+* SPI interface
+* Modular: you can use as many or as little as you need
+* Low-cost: No need to track down vintage high voltage driver chips that has been out of production for 30 years.
+
+Measuring only 2cm x 4cm, each of those tiny boards uses an STM32 to drive one Nixie tube. All digits and dots have hardware PWM for silky smooth dimming and animations, and each module is controlled via standard SPI interface, available on Arduino and Raspberry Pi (and virtually all embedded systems today).
+
+`dekunukem_gmail_com`
+
+[Full-size PDF](./joycon_pcb.pdf)