hide deprecated code; make USB snippet common for F0/F1/F3

F1:F103/deprecated/chronometer_v2/Readme.md

@@ -0,0 +1,42 @@
+Chronometer for downhill competitions
+=====================================
+
+The binary have two models: DEBUG (make debug) and RELEASE (make release or just make).
+DEBUGGing model use USART1 as debugging console, showing many messages.
+
+When typing commands you can fix them using backspace key. ESC-sequences don't work.
+
+## Pinout
+
+### Interfaces
+
+- PA11/12 -- USB
+- PA9(Tx), PA10 (Rx) -- USART1 (debug console / Bluetooth / GPS proxy)
+- PA2(Tx), PA3 -- USART2 (GPS)
+- PB10(Tx), PB11 -- USART3 (LIDAR / console)
+
+- PA13/14 - SWDIO
+
+### Other
+
+- PA1  -- PPS signal from GPS (EXTI)
+- PA8 -- Bluetooth "State" pin (not implemented yet)
+- PA15 -- USB pullup
+
+- PB0/1 -- TRIG0/1
+- PB3 -- TRIG2
+- PB8, PB9 -- onboard LEDs (PB8 - LED1, PB9 - LED0)
+
+- PC13 -- buzzer
+
+### LED screen:
+
+- PA5,6,7 (SCK, MISO, MOSI) -- SPI for LED screen: PA5/7 - SCK/MOSI, PA6 - SCLK/nOE (connected together)
+- PB6/7 -- A/B for LED screen
+
+## LEDS
+
+- LED0 -- shining when there's no PPS signal, fades for 0.25s on PPS
+- LED1 -- don't shines if no GPS found, shines when time not valid, blinks when time valid
+
+