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

F1:F103/deprecated/chronometer/Readme.md

@@ -0,0 +1,33 @@
+Chronometer for downhill competitions
+=====================================
+
+## Pinout
+
+- PA11/12 - USB
+- PA9(Tx),PA10 (debug mode) - USART1 - debug console
+- PA2(Tx), PA3 - USART2 - GPS
+- PB10(Tx), PB11 - USART3 - LIDAR - TRIG3
+
+- PA1  - PPS signal from GPS (EXTI)
+
+- PA4  - TRIG2 - 12V trigger (EXTI)
+- PA13 - TRIG0 - button0 (EXTI)
+- PA14 - TRIG1 - button1/laser/etc (EXTI)
+- PA15 - USB pullup
+
+- PB8, PB9 - onboard LEDs (0/1)
+
+- PC13 - buzzer
+
+## 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
+
+### Not implemented yet:
+
+- PA5,6,7 (SCK, MISO, MOSI) - SPI
+- PB0 - TRIG4 - ADC channel 8
+- PB6/7 (SCL, SDA) - I2C
+
+