How to Program NRF51422 w/S130 to read input pin into ADC

[CM]

I'm trying to replicate an Arduino Uno application where we connect a M3Q alcohol sensor into an analog pin and feed the data into the ADC. The specific board I have is made by Taiyo Yuden. I've gone through various code samples in Nordic Semiconductor's Github page (including this one) and I'm still unsure on how to setup the board to read the analog signal. If I understood correctly the code sample linked above they are trying to read data from BLE and send it to the ADC. In my application I want to read analog data from the sensor and then transmit it over bluetooth with the BLE module. Any help/tips on how to setup the ADC and read events after conversion will be greatly appreciated.

[Øyvind Karlsen]

Hi,

The code that you linked to reads the analog value from pin 1 and outputs it via UART and BLE. The output will be the 8bit int value from the ADC. The range in this particular example is from 0 to 3.6V, if you want to view the result in for example mV you can do the following: 3600*adc_result/255.

Best regards,

Øyvind

[CM]

Clarifying question: is it pin 1 as in "P0.01" of CN3? Or "Pin No 1" map as "P0.25" on the table (Page 4 of the Taiyo Yunden manual linked above in the question)? According to the Github sample, the adc_init() function uses ADC_CONFIG_PSEL_AnalogInput2 which maps to NRF_ADC_CONFIG_INPUT_2 based off header file "nrf_adc.h". I failed to see any reference to Pin 1 in the sample code. Will appreciate some further feedback.

[Øyvind Karlsen]

Hi,

It is PIN 1 as in P0.01. This is stated in comments in the start of the main file.