Configuration of GPIO and peripheral to receive characters asynchronously from an HyperTerminal (PC) in Interrupt mode with the Hardware Flow Control feature enabled. This example is based on STM32C0xx USART LL API. The peripheral initialization uses LL unitary service functions for optimization purposes (performance and size).
USART1 Peripheral is configured in asynchronous mode (115200 bauds, 8 data bit, 1 start bit, 1 stop bit, no parity). HW flow control is used. GPIO associated to User push-button is linked with EXTI.
Example execution:
After startup from reset and system configuration, LED4 is blinking quickly. On press on User push-button, USART TX Empty interrupt is enabled. First character of buffer to be transmitted is written into USART Transmit Data Register (TDR) in order to initialise transfer procedure. When character is sent from TDR, a TXE interrupt occurs. USART1 IRQ Handler routine is sending next character on USART Tx line. IT will be raised until last byte is to be transmitted : Then, Transmit Complete (TC) interrupt is enabled instead of TX Empty (TXE). When character is received on USART Rx line, a RXNE interrupt occurs. USART1 IRQ Handler routine is then checking received character value.
On a specific value (‘S’ or ‘s’), LED4 is turned On. Received character is echoed on Tx line.
In case of errors, LED4 is blinking.
Connectivity, UART/USART, Asynchronous, RS-232, baud rate, Interrupt, HyperTerminal, hardware flow control, CTS/RTS, Transmitter, Receiver
This example runs on STM32C031xx devices.
This example has been tested with NUCLEO-C031C6 board and can be easily tailored to any other supported device and development board.
NUCLEO-C031C6 Set-up :
GPIOs connected to USART1 TX/RX/CTS/RTS signals should be wired to corresponding pins on PC UART (could be done through a USB to UART adapter).
Launch serial communication SW on PC (as HyperTerminal or TeraTerm) with proper configuration (115200 bauds, 8 bits data, 1 stop bit, no parity, HW flow control enabled).
Launch the program. Enter characters on PC communication SW side.
In order to make the program work, you must do the following :