I2S CLK Outputs on nucleo-F446RE

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Posted on July 13, 2017 at 18:21The original post was too long to process during our migration. Please click on the attachment to read the original post.

[waclawek.jan]

Posted on July 17, 2017 at 17:10

Simplify.

Set up the I2S GPIOs and I2S itself (including PLL if you use it), then 'manually' feed data into its data register in a loop.

If still no activity at the given pins, read out the relevant GPIO and I2S registers content and compare to expected values according to RM, or post them.

JW

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Posted on July 28, 2017 at 10:53

Thanks for the tip! I am a bit too laizy to do this way, and I don't understand why the HAL would not work directly.

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Posted on July 28, 2017 at 15:52

Actually it is for an educational project and thus I need to go on the HAL + CubeMX way. Is it possible to get some support from @ST?

Looking at 

http://www.openstm32.org/forumthread2604

 I did exactly the same but no signal at all.

[Mohamed Jallouli_2 · Accepted solution]

Posted on July 28, 2017 at 16:29

Hello

Hoffet.Adrien

‌, Is the DMA mode circular or normal? If the DMA mode is normal, you might have missed the data when it was sent but that doesn't explain the missing clock signal.

Regards.

[waclawek.jan]

Posted on July 28, 2017 at 16:13

What exactly of what I've wrote above can't be done using Cube and the eclipsoid?

JW

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Posted on July 28, 2017 at 16:23

Haha nothing indeed, sorry I did not expressed myself correctly. I wanted to use the I2S api directly without going on the manual SPI thing...

However it is in fact working, what made me think that it was not:

• the clock is not sent when there is no data
• when you don't feed the buffer, no output is produced
• I was missing the one and only first data burst...

Thus I was not measuring anything...

Sorry I was not clear enough on how to operate with it.

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Posted on July 28, 2017 at 16:39

jalloulimedd

You spotted the issue, My DMA was in normal mode and the time I looked on my scope (that was in normal and not single shot), the clock pulse train was already finished. In circular mode it is way better !

Cheers!