Driver for the NXP PCT2075 digital temperature sensor and thermal watchdog
NXP PCT2075 temperature sensor driver for mbed
This library is a driver for the [NXP PCT2075](http://www.nxp.com/products/sensors/i2c-temperature-voltage-monitors/ic-bus-fm-plus-1-degree-c-accuracy-digital-temperature-sensor-and-thermal-watchdog:PCT2075). It only handles the I2C communication with the sensor, it does not handle the OS interrupt line. The [mbed InterruptIn](https://developer.mbed.org/handbook/InterruptIn) library can be used for this.
example usage
#include <mbed.h> #include <PCT2075.h> Serial s(USBTX, USBRX); // tx, rx InterruptIn TempPinInt(PC4); LowPowerTicker ticker; static volatile bool temp_int = false; static volatile bool tick_int = false; int main( void ) { TempPinInt.mode(PullUp); PCT2075::Configuration config = { PCT2075::OS_FAULT_QUE_1, PCT2075::OS_ACTIVE_LOW, PCT2075::OS_MODE_INTERRUPT, PCT2075::DEVICE_MODE_SHUTDOWN }; temp_sensor.set_configuration(config); temp_sensor.set_idle_time(PCT2075::TIDLE_MAX); temp_sensor.set_hyst_temperature(2000); temp_sensor.set_os_temperature(2500); TempPinInt.fall(&on_fall); ticker.attach(&tick, 2.0); while(true) { sleep(); // wait to be woken up by ticker or temp sensor if (tick_int) { s.printf("Tick\r\n"); config.device_mode = PCT2075::DEVICE_MODE_NORMAL; temp_sensor.set_configuration(config); tick_int = false; } if (temp_int) { config.device_mode = PCT2075::DEVICE_MODE_SHUTDOWN; temp_sensor.set_configuration(config); uint16_t t = temp_sensor.read_temperature(); s.printf("Temperature: %d\r\n", t); temp_int = false; } } }
PCT2075.h
- Committer:
- Seppe Stas
- Date:
- 2016-09-23
- Revision:
- 1:a2b7889eb4e9
File content as of revision 1:a2b7889eb4e9:
#ifndef _pct2075_h_ #define _pct2075_h_ #include "mbed.h" class PCT2075 { private: I2C &i2c; uint8_t address_write; uint8_t address_read; public: static const int16_t TEMP_MAX = 12500; // centi-°C static const int16_t TEMP_MIN = -5500; // centi-°C static const uint16_t TIDLE_MAX = 3100; // ms static const uint16_t TIDLE_MIN = 100; // ms // Fault queue is defined as the number of faults that must occur // consecutively to activate the OS output. It is provided to avoid false // tripping due to noise. Because faults are determined at the end of data // conversions, fault queue is also defined as the number of consecutive // conversions returning a temperature trip. enum OSFaultQue { OS_FAULT_QUE_1 = 0, OS_FAULT_QUE_2 = 1, OS_FAULT_QUE_4 = 2, OS_FAULT_QUE_6 = 3 }; enum OSPolarity { OS_ACTIVE_LOW = 0, OS_ACTIVE_HIGH = 1 }; enum OSMode { OS_MODE_COMP = 0, OS_MODE_INTERRUPT = 1 }; // In shutdown mode, the PCT2075 draws a small current of <1.0 µA and the // power dissipation is minimized; the temperature conversion stops, but the // I2C-bus interface remains active and register write/read operation can be // performed. When the shutdown is set, the OS output will be unchanged in // comparator mode and reset in interrupt mode. enum DeviceMode { DEVICE_MODE_NORMAL = 0, DEVICE_MODE_SHUTDOWN = 1 }; struct Configuration { OSFaultQue os_fault_que; OSPolarity os_polarity; OSMode os_mode; DeviceMode device_mode; }; PCT2075 (I2C &i2c_obj, uint8_t address = 0x48); ~PCT2075(); int16_t PCT2075_os_temp; int16_t PCT2075_hyst_temp; uint8_t PCT2075_temp_idle_cycle; Configuration get_configuration(); void set_configuration(Configuration& config); // Shorthand functions for changing one parameter of the configuration // without changing the other parameters. // Note: When changing multiple parameters it is more efficient to batch // them using set_configuration. void set_os_fault_queue(OSFaultQue fault_que); void set_os_polarity(OSPolarity polarity); void set_os_mode(OSMode mode); void set_device_mode(DeviceMode mode); void shutdown_mode(); void normal_mode(); // Returns the temperature in centi-degrees C, // resolution of .125 degrees, rounded down to .1 degrees int16_t read_temperature(); // Get the OS temperature in centi-degrees C, // rounded to .5 degrees C int16_t get_os_temperature(); // Set the OS temperature in centi-degrees C, // rounded to .5 degrees C void set_os_temperature(int16_t temperature); // Get the hysteresis temperature in centi-degrees C, // rounded to .5 degrees C int16_t get_hyst_temperature(); // Set the hysteresis temperature in centi-degrees C, // rounded to .5 degrees C void set_hyst_temperature(int16_t temperature); // Get idle time in ms, resolution of 100ms (deci-seconds) uint16_t get_idle_time(); // Set idle time in ms, rounded down to 100ms (deci-seconds) // In normal operation mode, the temp-to-digital conversion is executed // every 100 ms or other programmed value and the Temp register is updated // at the end of each conversion. During each ‘conversion period’ (Tconv) of // about 100 ms, the device takes only about 28 ms, called ‘temperature // conversion time’ (tconv(T)), to complete a temperature-to-data conversion // and then becomes idle for the time remaining in the period. This feature // is implemented to significantly reduce the device power dissipation. void set_idle_time(uint16_t time); }; #endif // _PCT2075_H_