main.cpp

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#include <Arduino.h>
#include <SPI.h>
 
#include "my_ADS126X.h"
 
// Chnage the following line to automatically use the correct pins for the board
// being tested (PT_Board, LC_Board, RTD_Board, or TC_Board)
#define PINS_ACTIVE_LAYOUT sense_board_pins::PT_Board
 
// This line MUST be after the #define PINS_ACTIVE_LAYOUT or it will override it
#include "sense_board_pins.h"
 
using sense_board_pins::Pins;
 
static ADS126X ads126x;
 
float convert_code_to_voltage(int32_t code) {
    // Assumes the 2.5V internal reference is being used!
    return ((float)code * 2.5f) / 2147483648.0f;
}
 
void setup() {
    Serial.begin(115200);
 
    // Setup SPI
    SPI.begin(Pins.ADC_SCLK, Pins.ADC_MISO, Pins.ADC_MOSI, Pins.ADC_CS_1);
 
    // You can set the freq if you want, or just use the default
    // SPI.setFrequency(1'000'000);
 
    // Due to the ADC output having valid data on FALLING CLK edges
    SPI.setDataMode(SPI_MODE1);
    pinMode(Pins.ADC_DRDY_1, INPUT);
 
    // Setup ADC
    ads126x.begin(Pins.ADC_CS_1);
 
    // Stop it while we config it, as suggested by datasheet
    ads126x.stopADC1();
 
    // If the two lines below are uncommented, the TDACs
    // will be connected to AIN6 and AIN7. This is useful for probing,
    // but makes the TDACs "see" our analog front end which could cause issues
    // ads126x.setOutputTDACP(1);
    // ads126x.setOutputTDACN(1);
 
    // Sets the positive TDAC to 3V, since we have 5V power
    ads126x.setOutputmagnitudeTDACP(ADS126X_TDAC_DIV_0_6);
 
    // Sets the negative TDAC to 2.5V, since we have 5V power
    ads126x.setOutputmagnitudeTDACN(ADS126X_TDAC_DIV_0_5);
 
    // Set the input to ADC1 to be the TDAC
    ads126x.setInputMux(ADS126X_TDAC, ADS126X_TDAC);
 
    // Bypas the PGA, so it does not affect measurements
    ads126x.bypassPGA();
 
    // Set the filter. You can change this to try different filters
    ads126x.setFilter(ADS126X_SINC4);
 
    // Set the datarate. You can change this, but the options depends on the
    // filter I do not know what happens if you program an invalid data rate for
    // a given filter
    ads126x.setRate(ADS126X_RATE_38400);
 
    // Start ADC now that configuration is done
    ads126x.startADC1();
}
 
void loop() {
    // Wait for DRDY pin
    while (digitalRead(Pins.ADC_DRDY_1) != LOW) {
        delayMicroseconds(10);
    }
 
    delayMicroseconds(25);
 
    // Get the most recent value
    const auto reading = ads126x.readADC1();
    Serial.print(F("TDAC reading: "));
    Serial.print(convert_code_to_voltage(reading.value), 6);
    Serial.println(" V");
 
    // Checks for invalid checksums, which signal corruption
    if (!reading.checksumValid) {
        Serial.println("Bad checksum!");
    }
}