Distance sensor- Embedded Systems Project
Fork of SRF02 by
SRF02.cpp
- Committer:
- el14ml
- Date:
- 2016-03-07
- Revision:
- 2:1e51f3230f2f
- Parent:
- 0:b729d2ce03bd
File content as of revision 2:1e51f3230f2f:
/** @file SRF02.cpp @brief Member functions implementations */ #include "mbed.h" #include "SRF02.h" SRF02::SRF02(PinName sdaPin, PinName sclPin) { i2c = new I2C(sdaPin,sclPin); // create new I2C instance and initialise i2c->frequency(400000); // I2C Fast Mode - 400kHz leds = new BusOut(LED3,LED2,LED1); } int SRF02::getDistanceCm() { char data[2]; // need to send CM command to command register data[0] = CMD_REG; data[1] = CM_CMD; int ack = i2c->write(SRF02_W_ADD,data,2); if (ack) error(); // if we don't receive acknowledgement, flash error message // this will start the sensor ranging, the datasheet suggests a delay of at least 65 ms before reading the result wait_ms(70); // we can now read the result - tell the sensor we want the high byte char reg = RANGE_H_REG; ack = i2c->write(SRF02_W_ADD,®,1); if (ack) error(); // if we don't receive acknowledgement, flash error message // if we read two bytes, the register is automatically incremented (H and L) ack = i2c->read(SRF02_R_ADD,data,2); if (ack) error(); // if we don't receive acknowledgement, flash error message // high byte is first, then low byte, so combine into 16-bit value return (data[0] << 8) | data[1]; } void SRF02::error() { while(1) { leds->write(7); wait(0.1); leds->write(0); wait(0.1); } }