Assignment of peripherals and pins
==================================
-I2C1 display
+SPI2 emulated TM1618 LED driver
USART1 debugging
+TIM3 TM1618 timeout
+TIM4 timing of IR remote control
Blue Pill pinout
+--------------------+
| VBATT 3.3V |
-BluePill LED | PC13 GND | display power
- | PC14 5V | display power (white side of connector)
+BluePill LED | PC13 GND |
+ | PC14 5V |
| PC15 PB9 |
- | PA0 PB8 | SFH5110 output (white side of connector)
- | PA1 PB7 | SDA1 display (white side of connector)
- | PA2 PB6 | SCL1 display
+ | PA0 PB8 |
+ | PA1 PB7 |
+ | PA2 PB6 |
| PA3 PB5 |
| PA4 PB4 |
| PA5 PB3 |
| PB0 PA11 |
| PB1 PA10 | RXD1 - debugging console
| PB10 PA9 | TXD1 - debugging console
- | PB11 PA8 |
- | RESET PB15 |
- | 3.3 V PB14 |
- | GND PB13 |
- | GND PB12 |
+ | PB11 PA8 | IR remote control
+ | RESET PB15 | MOSI2 - LED driver data input
+ | 3.3 V PB14 | MISO2 - unused
+ | GND PB13 | SCK2 - LED driver clock
+ | GND PB12 | SS2 - unused
+--------------------+