> I am trying to learn
Great.
Read the first 10 chapters in RM plus the USART chapter, read the datasheet and the errata. (USART=UART, i'll use the latter below)
Then, write blinky, ie. software which
- enables GPIO port clock in RCC
- configures the pin on which the LED is, to GPIO output
- in a loop, sets the pin, calls a loopdelay long enough so you can see the blinking, clears the pin, and calls the loopdelay again
Then modify blinky so that it stops blinking when you press a button, i.e.
- make sure you have in RCC enabled GPIO port clock of the GPIO port you use for the button
- configure the pin on which the button is, as GPIO input, enable pullup on that pin
- in the loop, when the GPIO input is cleared, wait
Then write software which configures UART and transmits some byte repeatedly, i.e.
- enable in RCC clock for GPIO port where the UART pins are located
- enable UART clock in RCC
- in GPIO, set the UART Tx pin to AF, make sure in AFIO that it's properly remapped or not, as needed (AFIO remap is 'F1-specific, it's different in other STM32)
- configure UART for required baudrate, enable Tx and enable UART
- in a loop, check if Tx register is empty (by checking UART_SR.TXE bit) write some byte to the UART data register, and then call the loopdelay
- using oscilloscope or logic analyzer, observe the UART Tx pin
Then write software which - on the second mcu, or on the same mcu in an other UART - receives data, i.e
- perform the same steps as above to enable and configure the UART Rx pin and UART itself, enabling UART
- perfrom the steps from the first post to configure GPIO pin on which the LED is located
- in a loop, wait until UART_SR RXNE is set
- read UART_DR, decide upon it whether LED has to be set to on or not
Or, you can click in CubeMX. or have a look at https://github.com/STMicroelectronics/STM32CubeF1/tree/master/Projects/STM32F103RB-Nucleo/Examples/UART/UART_TwoBoards_ComPolling (which is probably not CubeMX-generated). I don't use Cube.
JW
