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DMA uart transfers

Question asked by John Hite on Jan 27, 2017
Latest reply on Oct 9, 2017 by yoann LBY

I have been thrust into a situation where I realize I am in over my head. Eventually I think I will figure it out but could use a leg up with this STM32F437 device. I know little about it and especially it’s dma.

 

The project I have been assigned to uses DMA to communicate with the debug port UART8.

 

The DMAChannel is set to DMA_Channel_5, and from the table transmission for uart 8 is set for stream 0  and rx is stream6.

 

We are using Micrium uC/OS-III and in the interrupt vector table I see no interrupts setup for the UART but I do see an RxISR and a TxISR. From this should I assume that there is some smart linkage that lets the DMA know there are characters available at the UART.

 

AT startup the welcome banner is splashed. However when a character is entered to start the login process the system hangs up. Looking at the registers we see a transmit transfer error bit that will not clear.

 

My co-worker suspects that maybe it is due to dma transmit and receive happening at the same time but the documentation does not prohibit this as far as I know. So could this be a problem?

 

Thanks,

jh

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