How to use DMA on STM32L0 with FIFO threshold ?

[Alexandre T]

Posted on October 10, 2017 at 11:31

Hello,

I saw on the STM32L0 User Manual that FIFO mode and its threshold can be configured thanks to HAL_DMA_Init().

For a given stream, HAL_DMA_Init() API allows programming the required configuration

through the following parameters:- Transfer Direction- Source and Destination data formats- Circular, Normal or peripheral flow control mode- Channels Priority level- Source and Destination Increment mode- FIFO mode and its Threshold (if needed)- Burst mode for Source and/or Destination (if needed).

But I don't find where I can enable it and choose my threshold as I never used DMA before ?

[waclawek.jan · Accepted solution]

Posted on October 10, 2017 at 11:46

AFAIK the DMA in 'L0 (and 'F0/'L1/'L4) has no FIFO.

I guess this is some copy/paste artefact.

JW

[Alexandre T]

Posted on October 10, 2017 at 11:51

I found this

http://www.st.com/content/ccc/resource/technical/document/user_manual/41/78/8e/63/f9/32/44/12/DM00113898.pdf/files/DM00113898.pdf/jcr:content/translations/en.DM00113898.pdf

 page 50

[waclawek.jan]

Posted on October 10, 2017 at 12:11

That does not make it more real. Search for FIFO in the DMA chapter of the respective RM.

JW

[Alexandre T]

Posted on October 10, 2017 at 13:52

Well, nothing about FIFO in the

http://www.st.com/content/ccc/resource/technical/document/reference_manual/21/bd/0f/bd/1c/88/40/f0/DM00108282.pdf/files/DM00108282.pdf/jcr:content/translations/en.DM00108282.pdf

 ...

What does it mean, I can't put my device in FIFO mode if I want to use DMA ?

[waclawek.jan]

Posted on October 10, 2017 at 14:45

What do you mean by 'putting device in FIFO mode'?

DMA does not have FIFO.

Some of the peripherals do have some sort of  FIFO built into that peripheral.

JW

[Alexandre T]

Posted on October 10, 2017 at 14:53

I want to use DMA for my accelerometer to collect data without any loss (I discovered DMA yesterday).

On my accelerometer I can enable a 32 slots FIFO.

I wanted my DMA to collect the entire content of the FIFO at once thanks to the FIFO threshold, but it seems that I didn't undertand how to use DMA ?

[waclawek.jan]

Posted on October 10, 2017 at 15:16

A FIFO in an external device has nothing to do with FIFO in STM32 peripheral, nor in DMA.

JW