Has anyone written a sample-rate library/header for Maple ADC?

(2 posts) (2 voices)

ftb44
Member

Hi everyone,

I am about to use the Maple in a project with a little bit of DSP, and I am worried about the fact that I can only sample once per analogRead(). To me this suggests that my sample rate might not be constant! Has anyone written anything that could work around this non-determinism? I know that the Maple is capable of incredibly fast analog reads, and I have a few ideas on how to stabilize the time between samples--but I feel like there must be better coders out there who have already solved this problem.

Posted 2 years ago #
ventosus
Member

@fb44

The sampling of the ADC is by default configured to be triggered by software, but you can configure it to be triggered by a timer.

You have to use libmaple for that though. Here some keywords to look for in this forum and in the libmaple/wirish sources.

e.g. use:
adc_set_extsel(dev, ADC_EXT_EV_TIM1_CC1); // trigger by channel1 of timer1
when initializing the ADC peripheral instead of:
adc_set_extsel(dev, ADC_EXT_EV_SWSTART);

To get a notice about the end of conversion, you may want to
- monitor the end-of-conversion status flag (ADC_SR_EOC)
- set up an ADC interrupt (void __adc_irq(void))
- or use DMA if you want to sample more than one ADC channel

Posted 2 years ago #

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