UART Tx DMA variable length

[hosweetim]

Posted on November 25, 2015 at 03:39

I am currently using STM32F4 Discovery board, and i configure UART 2 into DMA mode for sending data.

i am able to send data with a fixed length to UART 2 using DMA.

But, i want to send data with a variable length.

Example

1:

Buffer = ''hello world!''

2: Buffer = ''is this working again?''

3: Buffer = ''i want to use dma tx mode''

I could do that by reconfiguring the DMA_Init, each before I send the data as shown below

DMA_InitStructure.DMA_Memory0BaseAddr = (uint32_t)Buffer;

DMA_InitStructure.DMA_BufferSize = (uint16_t)strlen(Buffer);

DMA_Init(DMA1_Stream5, &DMA_InitStructure);

Is this the right way to do it?

But, i read from the document, whenever I init the DMA, it will take sometime and there is a possibility that I could corrupt the previous DMA transfer.

May i know how to a proper way?

[Tesla DeLorean]

Posted on November 25, 2015 at 14:41

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The method for the F4 would be very similar, the code is probably overly verbose for clarity, but should give you are starting point. I may have built an F4 version of this, but this is the one that dropped out of a quick search.