How to set DMA Settings of USART1 of STM429ZI Nucleo board. How to cure?

[Da2]

I try to set DMA setting of USART1_RX, USART2_TX both. Bit MX Error message is occurred. as below figure.

[STTwo-32]

Hello @Da2 and welcome to the ST Community .

I can't reproduce your issue. can you share your .ioc file so we can test it?

Best Regards.

STTwo-32

[TDK · Accepted solution]

The chip has a limited amount of DMA streams. If all the streams possible for USART1 are being used for something else, you will be unable to add one for the USART1.

[Da2]

Refer the attached file. . RX and TX can not set DMA at same time.

[Da2]

Let me know how to set DMA Streams.

[TDK]

You can hover over the red area to find out the reason it can't be set. In this case, because it conflicts with UART8_RX.

Okay, now we know why it can't be enabled. But why does it conflict? Take a look in the reference manual at the DMA request mapping table and look at the entries for USART2_TX and UART8_RX. The only option is DMA1 stream 6, which can only be dedicated to one at a time.

Therefore, you cannot use DMA with USART2_TX and UART8_RX at the same time.

Your options are to use a different chip (outside the STM32F4 family), or use a different peripheral, or don't use DMA with one of them.

(Note that your post says USART1_RX, USART2_TX, but your IOC only has UART8_RX enabled. If you don't need UART8_RX just disable it and use USART2_TX instead.)

[Da2]

Thank you. Let me know the manual of Table 42. DMA1 request mapping.

[Da2]

I got manula from your home page. Thank you a lot.