Example of how to create an mbed library
Dependents: 2645_I2C_TMP102 Year2SensorProject Ranger EL15PJT_Ranger ... more
Diff: TMP102.cpp
- Revision:
- 0:8818842a3573
diff -r 000000000000 -r 8818842a3573 TMP102.cpp --- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/TMP102.cpp Fri Feb 05 17:24:06 2016 +0000 @@ -0,0 +1,85 @@ +// library implemtation file + +// obviously need to include the header +#include "TMP102.h" + +// we now implement each of the methods listed in the header + +// note the TMP102:: at the beginning of the method name +TMP102::TMP102(PinName sda, PinName scl) +{ + // in the constructor, we create the mbed API objects using 'new' + i2c_ = new I2C(sda,scl); + led_ = new DigitalOut(LED_RED); +} + +void TMP102::init() +{ + i2c_->frequency(400000); // set bus speed to 400 kHz + + int ack; // used to store acknowledgement bit + char config_data[2]; // array for data + char reg = CONFIG_REG; // register address + + //////// Read current status of configuration register /////// + + ack = i2c_->write(TMP102_W_ADD,®,1); // send the slave write address and the configuration register address + if (ack) + error(); // if we don't receive acknowledgement, flash error message + + ack = i2c_->read(TMP102_R_ADD,config_data,2); // read default 2 bytes from configuration register and store in array + if (ack) + error(); // if we don't receive acknowledgement, flash error message + + ///////// Configure the register ////////// + + // set conversion rate to 1 Hz - CR1 and CR2 are in the second data byte + config_data[1] |= (1 << 6); // set bit 6 + config_data[1] &= ~(1 << 7); // clear bit 7 + + //////// Send the configured register value to the slave config register //////////// + + // create data packet + char data_packet[3] = {reg,config_data[0],config_data[1]}; + + ack = i2c_->write(TMP102_W_ADD,data_packet,3); // send the data packet to the slave write address + if (ack) + error(); // if we don't receive acknowledgement, flash error message + +} + +void TMP102::read_temperature() +{ + int ack; // used to store acknowledgement bit + char data[2]; // array for data + char reg = TEMP_REG; // temperature register address + + ack = i2c_->write(TMP102_W_ADD,®,1); // send temperature register address + if (ack) + error(); // if we don't receive acknowledgement, flash error message + + ack = i2c_->read(TMP102_R_ADD,data,2); // read 2 bytes from temperature register and store in array + if (ack) + error(); // if we don't receive acknowledgement, flash error message + + int temperature = (data[0] << 4) | (data[1] >> 4); + + temperature_ = temperature*0.0625F; +} + +// temperature accessor method +float TMP102::get_temperature() +{ + read_temperature(); + return temperature_; +} + +void TMP102::error() +{ + while(1) { // if error, hang while flashing error message + led_->write(0); + wait(0.2); + led_->write(1); + wait(0.2); + } +} \ No newline at end of file