ads1015.cpp

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/**
 * I2C ADC chip
 *
 * never has been used in PROD? kill it?
 *
 */
 
#include "pch.h"
 
#if 0
 
#include "ads1015.h"
 
constexpr uint8_t addr = 0x48;
 
#define ADS1015_CONV (0)
#define ADS1015_CONFIG (1)
#define ADS1015_LO_THRESH (2)
#define ADS1015_HI_THRESH (3)
 
bool Ads1015::init(brain_pin_e scl, brain_pin_e sda) {
    if (!m_i2c.init(scl, sda)) {
        return false;
    }
 
    // ADS1015 has no ID register - so we read the Lo_thresh instead
    uint16_t loThresh = readReg(ADS1015_LO_THRESH);
 
    if (loThresh != 0x8000) {
        return false;
    }
 
    m_hasInit = true;
    return true;
}
 
void Ads1015::readChannels(float (&result)[4]) {
    for (size_t i = 0; i < 4; i++) {
        result[i] = readChannel(i);
    }
}
 
float Ads1015::readChannel(uint8_t channel) {
    // set the channel
    // set to +-6.144v full scale, fastest sampling, manual conversion start
    writeReg(ADS1015_CONFIG, 0xC1E0 | channel << 12);
 
    // Wait for conversion to complete
    // Bit is cleared while conversion is ongoing, set when done
    while ((readReg(ADS1015_CONFIG) & 0x8000) == 0) ;
 
    // Read the result
    int16_t result = readReg(ADS1015_CONV);
    // Result is 12 bits left aligned, so right align the result
    result = result >> 4;
 
    // 2048 counts = positive 6.144 volts
    constexpr float ratio = 6.144f / 2048;
    return result * ratio;
}
 
void Ads1015::writeReg(uint8_t reg, uint16_t data) {
    uint8_t packet[3];
 
    packet[0] = reg;
    packet[1] = data >> 8;
    packet[2] = data & 0xFF;
 
    m_i2c.write(addr, packet, 3);
}
 
uint16_t Ads1015::readReg(uint8_t reg) {
    uint16_t res;
    m_i2c.write(addr, &reg, 1);
    m_i2c.read(addr, reinterpret_cast<uint8_t*>(&res), 2);
    return SWAP_UINT16(res);
}
 
#endif // 0