Problems with SAADC

RE: Problems with SAADC

awneil — Thu, 02 May 2019 13:40:43 GMT

Yes - the Arduino "Ax" is not directly related to nRF52832 "AINx"

RE: Problems with SAADC

haakonsh — Thu, 02 May 2019 13:36:50 GMT

nrfx_saadc_sample_convert is a blocking call that disables the interrupts. See the function definition for details.

You need to use nrfx_saadc_sample to get a callback from the SAADC IRQ.

You will also need to run nrfx_saadc_calibrate_offset when you're initializing the SAADC.

RE: Problems with SAADC

danielb1194 — Wed, 01 May 2019 19:26:46 GMT

Thank you! That explains the A0 in the board then.. But the problem with the interrupt persist!

RE: Problems with SAADC

danielb1194 — Wed, 01 May 2019 19:26:30 GMT

So, the problem with the interrupt persists, the interrupt is never triggered, I am probably missing a step from the SAADC example in the SDK, however I do not know which step this is (maybe I need to set the interrupt, or enable it but I dont know how)

RE: Problems with SAADC

awneil — Wed, 01 May 2019 17:50:11 GMT

"A0" is the Arduino reference.

Fig 10 in the DK User Guide shows you which port pin connects where:

Fig 11 shows the Arduino references:

See also the "Pin Map" (Sheet 3) in the schematics:

RE: Problems with SAADC

danielb1194 — Wed, 01 May 2019 17:27:54 GMT

This seems to be working alright now.. looks like the board silk screen is lying since A0 is not really A0 (or maybe I am wrong) but the product specification states that A0 is P0.02 and the PCA10040 silk screen indicates that it is P0.03.

The product specification seems the be the ultimate source of truth in this case since now the ADC going from near zero when the input is like so. However the ADC still gives out negative numbers like -2 when near zero.

RE: Problems with SAADC

danielb1194 — Wed, 01 May 2019 15:20:42 GMT

So i commented out the lines that configure the buffer, and the function "sample_convert" works, but gives incorrect results from -2 to 40 (decimal)