101 lines
2.3 KiB
C++
101 lines
2.3 KiB
C++
#ifndef SENS_INA_219
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#define SENS_INA_219
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/** 1-Channel i2c volt/ampere sensor */
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template <typename I2C> class INA219 {
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private:
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I2C& i2c;
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static constexpr const uint8_t ADDR = 0b1000000;
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static constexpr const char* NAME = "INA219";
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static constexpr const uint8_t REG_CFG = 0x00;
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static constexpr const uint8_t REG_VS = 0x01; // shunt voltage
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static constexpr const uint8_t REG_VB = 0x02; // bus voltage
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public:
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struct Voltages {
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int16_t vShunt; // in uV * 10(!!!)
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int16_t vBus; // in mV
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int getMilliAmps(int shunt_milliOhm) const {
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return (vShunt * 10) / shunt_milliOhm;
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}
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};
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public:
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INA219(I2C& i2c) : i2c(i2c) {
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}
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/** get the current config */
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uint16_t getConfig() {
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uint8_t buf[2];
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i2c.readReg(ADDR, REG_CFG, 2, (uint8_t*)&buf);
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return getU16(buf);
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}
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/** read both voltages (shunt and bus) */
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Voltages getVoltages() {
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uint8_t buf[2];
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Voltages res;
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i2c.readReg(ADDR, REG_VS, sizeof(buf), buf);
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res.vShunt = getShuntVoltage(buf);
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i2c.readReg(ADDR, REG_VB, sizeof(buf), buf);
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res.vBus = getBusVoltage(buf);
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return res;
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}
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/** is an INA219 present on the bus? */
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bool isPresent() {
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return i2c.query(ADDR);
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}
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/*
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void dumpConfig() {
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const uint16_t cfg = getConfig();
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const uint8_t mode = (cfg & 0b00000000000111) >> 0;
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const uint8_t sadc = (cfg & 0b00000001111000) >> 3;
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const uint8_t badc = (cfg & 0b00011110000000) >> 7;
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const uint8_t pg = (cfg & 0b01100000000000) >> 11;
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const uint8_t brng = (cfg & 0b10000000000000) >> 13;
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printf("INA219\n");
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printf("- Mode: %d\n", mode);
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printf("- SADC: %d\n", sadc);
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printf("- BADC: %d\n", badc);
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printf("PG (shunt divider) %d\n", (1<<pg));
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if (brng) {printf("- bus voltage range [0:16]\n");}
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else {printf("- bus voltage range [0:32]\n");}
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}
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*/
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private:
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/** convert to bytes into a mV reading */
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int16_t getBusVoltage(const uint8_t* buf) {
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return (int16_t)((getU16(buf) >> 3) * 4); // lower 3 bits are status indicators -> remove, the LSB equals 4 mV -> * 4
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}
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/** convert to bytes into a uV reading */
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int16_t getShuntVoltage(const uint8_t* buf) {
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return (int16_t)getU16(buf); // NOTE: LSB = 10 uV
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}
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uint16_t getU16(const uint8_t* buf) {
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return ((buf[0] << 8) | (buf[1] << 0));
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}
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};
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#endif // SENS_INA_219
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