DMA-USART Example

m239955_stm1_st · ‎2013-09-03

Posted on September 03, 2013 at 14:51

hello,

at the moment i'm working on the DMA-USART example from the FW library to fit into my application.

the transmitting process(uC=> PC) is working as estimated, but the problem is i have to update the ''DMA_InitStructure.DMA_BufferSize '' (as you can see in line 216 \STM32F4xx_DSP_StdPeriph_Lib_V1.1.0\Project\STM32F4xx_StdPeriph_Examples\USART\USART_TwoBoards\USART_DataExchangeDMA)

Is it necessary to call everytime(for updating the BUFFERSIZE) to call the whole function in the main routine?

Is it normal to change this value ?

(as i have seen it in other examples till now, this value is only initialized once)

thanks, best regards

m

Tesla DeLorean · ‎2013-09-03

Posted on September 03, 2013 at 19:02

Not fm user id I presume? Not sure why the forum would let you use the same name, but suggest you change it to avoid confusion.

If you don't use circular mode you need to reprogram the DMA controller for each transfer. I personally haven't dug down to the minimal number of registers required to do so, but would imagine it would only take a handful.

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frankmeyer9 · ‎2013-09-03

Posted on September 03, 2013 at 19:54

Not fm user id I presume? Not sure why the forum would let you use the same name ...

No, it's not.

But with this crappy forum software, I don't wonder at all.

Just today it blew three of my post in a row ...

m239955_stm1_st · ‎2013-09-03

Posted on September 04, 2013 at 07:53

Hello,

no i'm not the same user as ''fm'' (sorry i didn't checked it before), yes it's strange that it's possible to allow the sam UN for different users.

thanks for you answer: ''If you don't use circular mode you need to reprogram the DMA controller for each transfer'' ! i suspected something like this.

best regards