USART_Communication_Rx_IT_Continuous_VCP_Init Example Description

This example shows how to configure GPIO and USART peripheral for continuously receiving characters from HyperTerminal (PC) in Asynchronous mode using Interrupt mode. Peripheral initialization is done using LL unitary services functions for optimization purpose (performance and size).

USART Peripheral is configured in asynchronous mode (115200 bauds, 8 data bit, 1 start bit, 1 stop bit, no parity). No 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 push button, USART RX Not Empty interrupt is enabled. When character is received on USART Rx line, a RXNE interrupt occurs. Received data is read from USART RDR register and stored in user buffer. A double buffer is available for received data, allowing continuous reception. User could process data received in Buffer A, while buffer B is used for reception. When buffer B is full, it could be handled by user, while buffer A becomes active buffer for next reception, and so on. Each time a reception buffer is full, user data process callback is called. Data processing consists in echoing data buffer content on PC Com port, and making LED4 toggle.

In case of errors, LED4 is blinking.

Virtual Com port feature of STLINK could be used for UART communication between board and PC.

Keywords

Connectivity, UART/USART, Asynchronous, RS-232, baud rate, Interrupt, HyperTerminal, Continuous Reception, VCP, Receiver

Directory contents

Hardware and Software environment

How to use it ?

In order to make the program work, you must do the following :