CCS/CC3200-LAUNCHXL: How setup frecuency sampling in ADC DMA

Hi,

As I have seen in the manual, the ADC sampling frequency is fixed at 62.5Ksps.

A. This would mean that to save a whole second you would need a 62500 * 2B = 125KB memory buffer for each channel. Is that correct?

B: In the Siddaram example a 640 buffer is used, will the DMA Interrupt occur every 10.24ms (16us * 640)?

C. Is there a way to configure the ADC to sample every 10ms and buffer all 100 samples through the DMA?

Thanks a lot.

A/B. I believe you calculations are correct.

C. I'm not sure (check the TRM), but you can try to increase the 640 to reduce the interrupt frequency.

Hi Kobi,

But the problem I would have is that to trigger the DMA Interuption every second, I would have to configure a 375KB buffer
(62500 * 2B * 3 chanels) for three Channels which is what I need, and the max RAM is 256K. It's not possible. Apart from that I only need
one sample every 10ms, so I'm wasting a lot of memory with unnecessary samples.

Thank you.

I don't see a way to configure the DMA in such way. You better wakeup every 10msec to collect the sample.

I don't think you lags is due to this timer interrupt (it is relatively a very short processing), which shouldn't have a an impact.

Br,

Kobi