nrf9160 analog input pins

[paul_tanner]

I got an example that uses PO.13 for analogue input.  It does this by referencing it as ADC_0.  That seemed to work OK when I hooked up to PO.13 on the nrf9160-DK

Then I changed the code to reference ADC_1 and hooked up P0.14.  This did not work and I'm note sure why.

Here's the relevant code -I changed 3 lines:

#define ADC_DEV "ADC_1"
#define ADC_1ST_CHANNEL_ID 1
#define ADC_1ST_CHANNEL_INPUT SAADC_CH_PSELP_PSELP_AnalogInput1

adc_dev = device_get_binding(ADC_DEV);

Error getting ADC_1 failed

Any suggestions please.  Perhaps something else is not defined?

[Charlie]

Hi Paul,

This is as expected, nRF9160 only has one ADC peripheral which is ADC_0.

Best regards,

Charlie

[paul_tanner]

From Objective Product Spec:

6.12.4 Analog inputs and channels

Up to eight analog input channels, CH[n](n=0..7), can be configured.

[Charlie]

One ADC peripheral has eight channels.

[paul_tanner]

So how do you configure the other 7 channels onto pins PO.14 onwards?

I want to monitor multiple inputs, albeit not simultaneously.

Regards.

[Charlie]

nRF9160 ADC is similar to nRF5x devices. You can refer to this ticket: Configuring ADC sampling rate and simultaneous reading from multiple channels.

[paul_tanner]

That wasn't much help.

This was:

#define ADC_DEV "ADC_0"
#define ADC_1ST_CHANNEL_ID 1
#define ADC_1ST_CHANNEL_INPUT NRF_SAADC_INPUT_AIN1

Evidently, NRF_SAADC_INPUT_AIN1 is a synonym for P0.14