Скачать или смотреть Creating an STM32 Uart Bridge

Learn how to build a reliable UART bridge using STM32F072CB, with DMA and HAL libraries for seamless data transmission.
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This video is based on the question https://stackoverflow.com/q/70884630/ asked by the user 'Ignacio Islas' ( https://stackoverflow.com/u/18051271/ ) and on the answer https://stackoverflow.com/a/70919830/ provided by the user 'YJ Kim' ( https://stackoverflow.com/u/18053667/ ) at 'Stack Overflow' website. Thanks to these great users and Stackexchange community for their contributions.

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Building an STM32 UART Bridge

In the world of embedded systems, bridging two UART interfaces can be a bit of a challenge, especially when maintaining reliable communication between them. If you are working with an STM32F072CB microcontroller, you've probably encountered the need to ensure that data received on one UART is correctly sent over the other UART, and vice versa. This guide will walk you through the process of creating a UART bridge using DMA to handle data transmission efficiently.

Understanding the Problem

You want to create a bridge between two UART ports where:

Data coming into UART1 RX should be sent out through UART2 TX.

Data coming into UART2 RX should be sent out through UART1 TX.

Both UARTs must operate at the same baud rate to avoid data corruption. Additionally, using Direct Memory Access (DMA) can significantly reduce CPU load during operation. The challenge arises when the HAL_UART_Transmit function blocks code execution until all bytes are sent, thus leading to data loss if new data arrives during transmission.

Implementation Steps

1. Initialize the UART and DMA

To get started, you need to initialize your UART communications and configure DMA. Below is a snippet that delves into this setup.

[[See Video to Reveal this Text or Code Snippet]]

2. Process Incoming Data

Next, you need to implement a callback function that will handle the incoming data. This function needs to use DMA for transmission to avoid the blocking behavior of HAL_UART_Transmit.

Here is an improved version of your callback function:

[[See Video to Reveal this Text or Code Snippet]]

3. Important Considerations

Avoiding Data Loss

Directly transmitting the RX buffer can lead to data corruption. If new data arrives during transmission, it can overwrite the data being sent. To prevent this, always copy the RX buffer to a separate TX buffer before transmission.

Consider re-enabling DMA after copying the data rather than immediately after transmission, to ensure data integrity.

Conclusion

Setting up a UART bridge with an STM32 microcontroller involves careful management of receive and transmit buffers, especially when integrating DMA to facilitate efficient data handling. By following the steps outlined above, you should be able to create a robust UART bridge that minimizes CPU utilization while ensuring reliable data exchange between your two UART interfaces. Happy coding!