CoCalc -- AP_ADC_ADS1115.cpp

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GitHub Repository: Ardupilot/ardupilot
Path: blob/master/libraries/AP_ADC/AP_ADC_ADS1115.cpp
Views: ¹⁷⁹⁸
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#include <AP_HAL/AP_HAL.h>
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#include <AP_HAL/utility/sparse-endian.h>
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#include "AP_ADC_ADS1115.h"
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#define ADS1115_ADDRESS_ADDR_GND    0x48 // address pin low (GND)
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#define ADS1115_ADDRESS_ADDR_VDD    0x49 // address pin high (VCC)
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#define ADS1115_ADDRESS_ADDR_SDA    0x4A // address pin tied to SDA pin
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#define ADS1115_ADDRESS_ADDR_SCL    0x4B // address pin tied to SCL pin
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#define ADS1115_I2C_ADDR            ADS1115_ADDRESS_ADDR_GND
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#define ADS1115_I2C_BUS             1
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#define ADS1115_RA_CONVERSION       0x00
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#define ADS1115_RA_CONFIG           0x01
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#define ADS1115_RA_LO_THRESH        0x02
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#define ADS1115_RA_HI_THRESH        0x03
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#define ADS1115_OS_SHIFT            15
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#define ADS1115_OS_INACTIVE         0x00 << ADS1115_OS_SHIFT
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#define ADS1115_OS_ACTIVE           0x01 << ADS1115_OS_SHIFT
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#define ADS1115_MUX_SHIFT           12
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#define ADS1115_MUX_P0_N1           0x00 << ADS1115_MUX_SHIFT /* default */
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#define ADS1115_MUX_P0_N3           0x01 << ADS1115_MUX_SHIFT
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#define ADS1115_MUX_P1_N3           0x02 << ADS1115_MUX_SHIFT
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#define ADS1115_MUX_P2_N3           0x03 << ADS1115_MUX_SHIFT
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#define ADS1115_MUX_P0_NG           0x04 << ADS1115_MUX_SHIFT
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#define ADS1115_MUX_P1_NG           0x05 << ADS1115_MUX_SHIFT
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#define ADS1115_MUX_P2_NG           0x06 << ADS1115_MUX_SHIFT
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#define ADS1115_MUX_P3_NG           0x07 << ADS1115_MUX_SHIFT
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#define ADS1115_PGA_SHIFT           9
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#define ADS1115_PGA_6P144           0x00 << ADS1115_PGA_SHIFT
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#define ADS1115_PGA_4P096           0x01 << ADS1115_PGA_SHIFT
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#define ADS1115_PGA_2P048           0x02 << ADS1115_PGA_SHIFT // default
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#define ADS1115_PGA_1P024           0x03 << ADS1115_PGA_SHIFT
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#define ADS1115_PGA_0P512           0x04 << ADS1115_PGA_SHIFT
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#define ADS1115_PGA_0P256           0x05 << ADS1115_PGA_SHIFT
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#define ADS1115_PGA_0P256B          0x06 << ADS1115_PGA_SHIFT
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#define ADS1115_PGA_0P256C          0x07 << ADS1115_PGA_SHIFT
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#define ADS1115_MV_6P144            0.187500f
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#define ADS1115_MV_4P096            0.125000f
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#define ADS1115_MV_2P048            0.062500f // default
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#define ADS1115_MV_1P024            0.031250f
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#define ADS1115_MV_0P512            0.015625f
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#define ADS1115_MV_0P256            0.007813f
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#define ADS1115_MV_0P256B           0.007813f
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#define ADS1115_MV_0P256C           0.007813f
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#define ADS1115_MODE_SHIFT          8
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#define ADS1115_MODE_CONTINUOUS     0x00 << ADS1115_MODE_SHIFT
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#define ADS1115_MODE_SINGLESHOT     0x01 << ADS1115_MODE_SHIFT // default
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#define ADS1115_RATE_SHIFT          5
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#define ADS1115_RATE_8              0x00 << ADS1115_RATE_SHIFT
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#define ADS1115_RATE_16             0x01 << ADS1115_RATE_SHIFT
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#define ADS1115_RATE_32             0x02 << ADS1115_RATE_SHIFT
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#define ADS1115_RATE_64             0x03 << ADS1115_RATE_SHIFT
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#define ADS1115_RATE_128            0x04 << ADS1115_RATE_SHIFT // default
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#define ADS1115_RATE_250            0x05 << ADS1115_RATE_SHIFT
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#define ADS1115_RATE_475            0x06 << ADS1115_RATE_SHIFT
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#define ADS1115_RATE_860            0x07 << ADS1115_RATE_SHIFT
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#define ADS1115_COMP_MODE_SHIFT         4
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#define ADS1115_COMP_MODE_HYSTERESIS    0x00 << ADS1115_COMP_MODE_SHIFT        // default
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#define ADS1115_COMP_MODE_WINDOW        0x01 << ADS1115_COMP_MODE_SHIFT
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#define ADS1115_COMP_POL_SHIFT          3
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#define ADS1115_COMP_POL_ACTIVE_LOW     0x00 << ADS1115_COMP_POL_SHIFT     // default
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#define ADS1115_COMP_POL_ACTIVE_HIGH    0x01 << ADS1115_COMP_POL_SHIFT
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#define ADS1115_COMP_LAT_SHIFT          2
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#define ADS1115_COMP_LAT_NON_LATCHING   0x00 << ADS1115_COMP_LAT_SHIFT    // default
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#define ADS1115_COMP_LAT_LATCHING       0x01 << ADS1115_COMP_LAT_SHIFT
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#define ADS1115_COMP_QUE_SHIFT      0
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#define ADS1115_COMP_QUE_ASSERT1    0x00 << ADS1115_COMP_SHIFT
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#define ADS1115_COMP_QUE_ASSERT2    0x01 << ADS1115_COMP_SHIFT
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#define ADS1115_COMP_QUE_ASSERT4    0x02 << ADS1115_COMP_SHIFT
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#define ADS1115_COMP_QUE_DISABLE    0x03 // default
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#define ADS1115_DEBUG 0
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#if ADS1115_DEBUG
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#include <cstdio>
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#define debug(fmt, args ...)  do {hal.console->printf("%s:%d: " fmt "\n", __FUNCTION__, __LINE__, ## args); } while(0)
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#define error(fmt, args ...)  do {fprintf(stderr,"%s:%d: " fmt "\n", __FUNCTION__, __LINE__, ## args); } while(0)
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#else
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#define debug(fmt, args ...)
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#define error(fmt, args ...)
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#endif
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extern const AP_HAL::HAL &hal;
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#define ADS1115_CHANNELS_COUNT           6
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const uint8_t AP_ADC_ADS1115::_channels_number  = ADS1115_CHANNELS_COUNT;
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/* Only two differential channels used */
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static const uint16_t mux_table[ADS1115_CHANNELS_COUNT] = {
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    ADS1115_MUX_P1_N3,
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    ADS1115_MUX_P2_N3,
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    ADS1115_MUX_P0_NG,
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    ADS1115_MUX_P1_NG,
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    ADS1115_MUX_P2_NG,
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    ADS1115_MUX_P3_NG
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};
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AP_ADC_ADS1115::AP_ADC_ADS1115()
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    : _dev{}
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    , _gain(ADS1115_PGA_4P096)
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    , _channel_to_read(0)
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{
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    _samples = NEW_NOTHROW adc_report_s[_channels_number];
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}
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AP_ADC_ADS1115::~AP_ADC_ADS1115()
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{
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    delete[] _samples;
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}
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bool AP_ADC_ADS1115::init()
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{
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    _dev = hal.i2c_mgr->get_device(ADS1115_I2C_BUS, ADS1115_I2C_ADDR);
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    if (!_dev) {
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        return false;
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    }
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    _gain = ADS1115_PGA_4P096;
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    _dev->register_periodic_callback(100000, FUNCTOR_BIND_MEMBER(&AP_ADC_ADS1115::_update, void));
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    return true;
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}
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bool AP_ADC_ADS1115::_start_conversion(uint8_t channel)
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{
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    struct PACKED {
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        uint8_t reg;
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        be16_t val;
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    } config;
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    config.reg = ADS1115_RA_CONFIG;
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    config.val = htobe16(ADS1115_OS_ACTIVE | _gain | mux_table[channel] |
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                         ADS1115_MODE_SINGLESHOT | ADS1115_COMP_QUE_DISABLE |
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                         ADS1115_RATE_250);
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    return _dev->transfer((uint8_t *)&config, sizeof(config), nullptr, 0);
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}
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size_t AP_ADC_ADS1115::read(adc_report_s *report, size_t length) const
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{
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    for (size_t i = 0; i < length; i++) {
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        report[i].data = _samples[i].data;
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        report[i].id = _samples[i].id;
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    }
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    return length;
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}
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float AP_ADC_ADS1115::_convert_register_data_to_mv(int16_t word) const
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{
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    float pga;
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    switch (_gain) {
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    case ADS1115_PGA_6P144:
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        pga = ADS1115_MV_6P144;
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        break;
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    case ADS1115_PGA_4P096:
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        pga = ADS1115_MV_4P096;
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        break;
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    case ADS1115_PGA_2P048:
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        pga = ADS1115_MV_2P048;
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        break;
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    case ADS1115_PGA_1P024:
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        pga = ADS1115_MV_1P024;
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        break;
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    case ADS1115_PGA_0P512:
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        pga = ADS1115_MV_0P512;
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        break;
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    case ADS1115_PGA_0P256:
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        pga = ADS1115_MV_0P256;
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        break;
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    case ADS1115_PGA_0P256B:
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        pga = ADS1115_MV_0P256B;
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        break;
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    case ADS1115_PGA_0P256C:
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        pga = ADS1115_MV_0P256C;
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        break;
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    default:
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        pga = 0.0f;
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        DEV_PRINTF("Wrong gain");
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        AP_HAL::panic("ADS1115: wrong gain selected");
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        break;
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    }
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    return (float) word * pga;
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}
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void AP_ADC_ADS1115::_update()
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{
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    uint8_t config[2];
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    be16_t val;
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    if (!_dev->read_registers(ADS1115_RA_CONFIG, config, sizeof(config))) {
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        error("_dev->read_registers failed in ADS1115");
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        return;
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    }
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    /* check rdy bit */
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    if ((config[1] & 0x80) != 0x80 ) {
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        return;
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    }
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    if (!_dev->read_registers(ADS1115_RA_CONVERSION, (uint8_t *)&val,  sizeof(val))) {
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        return;
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    }
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    float sample = _convert_register_data_to_mv(be16toh(val));
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    _samples[_channel_to_read].data = sample;
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    _samples[_channel_to_read].id = _channel_to_read;
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    /* select next channel */
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    _channel_to_read = (_channel_to_read + 1) % _channels_number;
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    _start_conversion(_channel_to_read);
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}
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