- STM32F103C8T6 "Blue Pill"
- TFT ILI9341 screen
- Ultrasonic sensor HC-SR04
screen STM32F103
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MISO PA6 (MISO1)
LED 3V3
SCK PA5 (SCK1)
MOSI PA7 (MOSI1)
DC/RS PA0
RESET PA1
CS PA4 (NSS1)
GND GND
VCC 3V3
Serial Debug
GND GND
RX PA2 (TX2)
TX PA3 (RX2)
US HC-SR04
GND GND
VCC 5V
TRIGGER PA8 (T1C1)
ECHO PB6 (T4C1)
A Timer PWM signal on the TRIGGER pin generates a pulse regularly while the ECHO pin is connected to another Timer in Input Capture mode.
The Input Capture timer has a frequency of 1 MHz to get capture values in microseconds. The difference of capture values between the rising and falling edges gives the pulse width.