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; } } }
Diff: PCT2075.h
- Revision:
- 1:a2b7889eb4e9
--- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/PCT2075.h Fri Sep 23 15:38:34 2016 +0200 @@ -0,0 +1,109 @@ +#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_