UART and USART problem

[dixon]

Posted on November 03, 2016 at 15:40

Hi I had configured a the UART_DMA_ hyperterminal program for the evaluation board newly by cubemx and its working fine by USART_1. But whenI configured it for UART_8 for my mcu its sending the characters but I cant recieve it. Is there any major difference between uart and usart in asynchronous mode. Please help. I am stuck

[slimen]

Posted on November 03, 2016 at 16:15

Hello,

Could you precise which device are you using?

For more details/clarification about USART/UART mode, you can refer to your product reference manual, in ''Universal synchronous asynchronous receiver transmitter (USART)'' section.

Regards

[Tesla DeLorean]

Posted on November 03, 2016 at 17:14

It is important to specify the specific part in question, it is hard, and unnecessary to have to wade through older threads to determine context.

On several STM32 parts not all UART support DMA, DMA Channels/Streams are also a limited resource, with limited flexibility. ie easy to get conflicts, and run out of options. Review the Reference Manuals to determine what does what.

The UART is a subset of the USART functionality, very few people use the Synchronous mode, and it is far from a optimum implementation. The UART also tend to be on the slower APB bus, but likely not an issue for sub-Mbps implementations.

DMA for USART/UART works most effectively for larger buffer TX operations, ideally where you can transmit data in place rather than copying into other buffers.

[dixon]

Posted on November 04, 2016 at 14:09

Thank you for the reply. Iam using STM32F429VIT6. Both have the DMA channel and stream. I have checked with the same USART_1 too. The MCU cant recieve the string that I transmit but the mcu can ttransmit another string. But it is working fine with the evaluuation board. Only difference is they are using a transeiver IC in that. But I hhave input 3.3 v only to the MCU.

 

[Tesla DeLorean]

Posted on November 04, 2016 at 16:43

Not something I can debug/diagnose with the information provided, also not supporting HAL/CubeMX

Suggest you use a Scope or Analyzer, and make some determination about the signals.