C++ driver software code for Maxim Integrated MAX31723/MAX31722 device temperature sensor. The MAX31723 provides 9 to 12 bits of resolution.
Dependents: MAX31723_Thermostat_Thermometer_Sensor
Diff: max31723.cpp
- Revision:
- 8:e310e55a687b
- Parent:
- 6:2e49aa7fa091
--- a/max31723.cpp Tue Feb 12 22:58:59 2019 +0000 +++ b/max31723.cpp Wed Feb 13 22:26:50 2019 +0000 @@ -37,6 +37,10 @@ uint8_t lsb; uint8_t msb; }; + struct { + uint16_t magnitude_bits:15; + uint16_t sign_bit:1; + }; uint16_t uwrd; int16_t swrd; }; @@ -70,12 +74,14 @@ float MAX31723::read_reg_as_temperature(uint8_t reg) { - max31723_raw_data raw; + max31723_raw_data tmp; float temperature; if (reg >= MAX31723_REG_TEMP_LSB && reg <= MAX31723_REG_MAX) { - read_reg(raw.lsb, reg); - read_reg(raw.msb, reg+1); - temperature = raw.swrd * MAX31723_CF_LSB; + read_reg(tmp.lsb, reg); + read_reg(tmp.msb, reg+1); + temperature = tmp.magnitude_bits * MAX31723_CF_LSB; + if (tmp.sign_bit) + temperature = -temperature; return temperature; } else { printf("Input read_registers_as_temperature is invalid, %d r\n", @@ -129,8 +135,13 @@ { int ret; max31723_raw_data raw; + raw.uwrd = 0; + if (temperature < 0) { + raw.sign_bit = 1; + temperature = -temperature; + } temperature /= MAX31723_CF_LSB; - raw.swrd = int16_t(temperature); + raw.magnitude_bits = uint16_t(temperature); ret = write_reg(raw.lsb, MAX31723_WRITE_MASK | MAX31723_REG_TRIP_LO_LSB); wait(.015); ret = write_reg(raw.msb, MAX31723_WRITE_MASK | MAX31723_REG_TRIP_LO_MSB); @@ -142,8 +153,13 @@ { int ret; max31723_raw_data raw; + raw.uwrd = 0; + if (temperature < 0) { + raw.sign_bit = 1; + temperature = -temperature; + } temperature /= MAX31723_CF_LSB; - raw.swrd = int16_t(temperature); + raw.magnitude_bits = uint16_t(temperature); ret = write_reg(raw.lsb, MAX31723_WRITE_MASK | MAX31723_REG_TRIP_HI_LSB); wait(.015); ret = write_reg(raw.msb, MAX31723_WRITE_MASK | MAX31723_REG_TRIP_HI_MSB);