STM32 SPI DMA for External SPI DAC

fabio1 · ‎2014-01-25

Posted on January 25, 2014 at 21:34

Hi,

I am trying to sample some data using DMA and the internal ADC and send the same data , still using DMA to an external DAC using the SPI Internface, through an optoisolation barrier.

It all works great, I need 1MS/s and this is not a problem.

Still I need to qualify the data using a NSS line and TI Mode works fine, but the lack of wait states makes my task hard.

The NSS is released on the 14th byte and re-issued on the 15th. Most of the DACs (I have been using DAC8311 for a while) need some time between the sync signal and the new data, so the NSS line needs to be inactive for a while between the subsequent data.

I could not find any suitable DAC.

Is the interface not suitable for such a task or am I missing something?

Thanks

Fabio

franck2 · ‎2014-11-24

Posted on November 24, 2014 at 15:46

Hi Fabio,

Same question as Blaz.

How did you configure the SPI? Do you require any additional code to start the transfer?

Thank you for your answers,

Franck

franck2 · ‎2014-11-24

Posted on November 24, 2014 at 15:48

Or did sending a word to the DMA controller may be sufficient to enable an SPI transaction?

franck2 · ‎2014-11-26

Posted on November 26, 2014 at 11:24

Hi Blaz,

I ask again my question:

How did you configure the SPI? Do you require any additional code to start the transfer?

Thanks for your reply.

Franck