Low Power SAADC

RE: Low Power SAADC

bryanhsieh — Mon, 16 Oct 2017 15:32:47 GMT

I am guessing with a oversampling rate of 4 and 4 channels enabled, the average power would be 1.5 * 4 * 4 * total_acquisition time / 5ms if low power was working.

RE: Low Power SAADC

Jørgen Holmefjord — Mon, 16 Oct 2017 15:26:54 GMT

Sorry I missed that, with burst enabled, oversampling should work as expected. You are correct that the SAADC will add the EasyDMA current of ~1.5 mA when it is enabled. The point of the low power mode is to disable the SAADC peripheral between samples. If you have a slow sample rate, this can save much on the average current consumption.

RE: Low Power SAADC

bryanhsieh — Mon, 16 Oct 2017 15:16:45 GMT

Thanks Jorgen, I have found the problem was with how I initialized the channels. I don't quite understand why oversampling with scan mode is not a good idea, as I have burst enabled as suggested by that post and it seems to be working. What I have found is that even with low power enabled the current still increased by nearly 1.5mA with ADC on which I think is the easy DMA current. So that it makes no difference to turn on low power on not but at least the code runs now.

RE: Low Power SAADC

Jørgen Holmefjord — Mon, 16 Oct 2017 15:03:10 GMT

Hi Bryan,

Could you check if the example in this post is working for you?

Also note that you might not want to use oversampling with scan mode, due to the reason described in this post.

Best regards,

Jørgen