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Dear friends,
I am puzzled with AT91SAM7X SPI w/DMA. I can't see that it is usable for peripherals which use CS cycling for every word (it is fast 16 bit DAC). We tried 16 bit wide SPI, CS remained low during the transfer of a whole buffer (fixed CS), then we tried 32 bit word length (variable CS), but all we got were hickups, skipping parts of buffer etc. Than, we tried interrupt driven transfer, but it was limited to about 100 KSPS. It seems that interrupt overhead is about 4 times bigger than on AVR devices.
Can anyone help me, or I should put AT91 in trash?
Best regards
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