SAADC Snippet cannot follow

RE: SAADC Snippet cannot follow

Nats — Wed, 27 May 2020 14:50:44 GMT

Thank you very much. That is helpful

RE: SAADC Snippet cannot follow

hmolesworth — Thu, 21 May 2020 15:49:17 GMT

  NRF_SAADC->CH[0].PSELP = PSELP_AnalogInput0 << SAADC_CH_PSELP_PSELP_Pos;

RE: SAADC Snippet cannot follow

Nats — Thu, 21 May 2020 11:43:04 GMT

Yes, sorry for the mistake.

Can you tell me how to read from pin A0, using this code?

RE: SAADC Snippet cannot follow

Karl Ylvisaker — Wed, 20 May 2020 10:21:43 GMT

Hello,

It is true as @hmolesworth says, if you look at the lines of code he shared you will see that the SAADC channel measures the VDD using single-ended input.
Let me know if anything still should be unclear!

As a side note, it seems the link you meant to post is the SAADC sample, not the TEMP sensor sample which you linked in your ticket.

Best regards,
Karl

P.S Thank you @hmolesworth for your swift reply!

RE: SAADC Snippet cannot follow

hmolesworth — Tue, 19 May 2020 20:16:10 GMT

That code is not reading pin A0; See this:

  // Configure the SAADC channel with VDD as positive input, no negative input(single ended).
  NRF_SAADC->CH[0].PSELP = SAADC_CH_PSELP_PSELP_VDD << SAADC_CH_PSELP_PSELP_Pos;
  NRF_SAADC->CH[0].PSELN = SAADC_CH_PSELN_PSELN_NC << SAADC_CH_PSELN_PSELN_Pos;

This information will help:

// Analog positive and negative input channels have strange numbering:
//  PSELP_NC           0UL  Not connected
//  PSELP_AnalogInput0 1UL  AIN0
//  PSELP_AnalogInput1 2UL  AIN1
//  PSELP_AnalogInput2 3UL  AIN2
//  PSELP_AnalogInput3 4UL  AIN3
//  PSELP_AnalogInput4 5UL  AIN4
//  PSELP_AnalogInput5 6UL  AIN5
//  PSELP_AnalogInput6 7UL  AIN6
//  PSELP_AnalogInput7 8UL  AIN7
//  PSELP_VDD          9UL  VDD