SAMD21 maximum frequency DMA

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Hello!

Following the example made a configuration on the picture, the SPI works,
but if I raise the frequency of Generic cg0 from 4 MHz to 8 MHz the SPI not work,

who knows what the problem is in the check?

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dav1977 wrote:
SPI not work

In what way(s), exactly, does it "not work" ?

 

Do you mean the SPI peripheral does "not work" (sic), or is it your code that does "not work" (sic) - or what?

 

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Symptom that SPI does not work there are no clock pulses,

my code works, the other pins are switched (select).

 

Similarly, SPI ceases to work when the Baud Rade 500k instead of 50k,
debugger has nothing to DMA hardware module.

 

the documentation says nothing about restrictions.

Last Edited: Wed. Aug 22, 2018 - 11:42 AM
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??

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Is there any reason why to use different clock domains? It always bring issues as synchronization between clock domains has to be handled by user. first, try to use only one GCLK, GCLK0 as source for all peripherals is recommended. To reduce frequency a divider shall be used as necessary.

SPI is just simple shift register which completely does not care about frequency. it will by faster or slower..