88 lines
2.1 KiB
C
88 lines
2.1 KiB
C
/*
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* An interface to the TI TMP102 temperature sensor
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* 12 bit temperature reading, 0.5 deg. Celsius accuracy
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* -----------------------------------------------------------------
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*
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* Author : Hedde Bosman (heddebosman@incas3.eu)
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*/
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#include "contiki.h"
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#include "lib/sensors.h"
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#include "dev/tmp102-sensor.h"
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#ifndef bool
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#define bool uint8_t
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#endif
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#ifndef false
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#define false 0
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#endif
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#ifndef true
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#define true 1
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#endif
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static void set_configuration(uint8_t rate, bool precision) {
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uint8_t tx_buf[] = {TMP102_REGISTER_CONFIGURATION,
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0,
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(precision ? TMP102_CONF_EXTENDED_MODE : 0) | ((rate << 6) & TMP102_CONF_CONVERSION_RATE)
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};
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i2c_transmitinit(TMP102_ADDR, 3, tx_buf);
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}
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/*---------------------------------------------------------------------------*/
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static int value(int type) {
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uint8_t reg = TMP102_REGISTER_TEMPERATURE;
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uint8_t temp[2];
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int16_t temperature = 0;
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/* transmit the register to start reading from */
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i2c_transmitinit(TMP102_ADDR, 1, ®);
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while (!i2c_transferred()); // wait for data to arrive
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/* receive the data */
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i2c_receiveinit(TMP102_ADDR, 2, temp);
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while (!i2c_transferred()); // wait for data to arrive
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// 12 bit normal mode
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temperature = ((temp[0] <<8) | (temp[1])) >> 4; // lsb
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// 13 bit extended mode
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//temperature = ((temp[0] <<8) | (temp[1])) >> 3; // lsb
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temperature = (100*temperature)/16; // in 100th of degrees
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return temperature;
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}
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/*---------------------------------------------------------------------------*/
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static int status(int type) {
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switch (type) {
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case SENSORS_ACTIVE:
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case SENSORS_READY:
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return 1; // fix?
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break;
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}
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return 0;
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}
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/*---------------------------------------------------------------------------*/
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static int configure(int type, int c) {
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switch (type) {
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case SENSORS_ACTIVE:
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if (c) {
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// set active
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set_configuration(1, false); // every 1 second, 12bit precision
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} else {
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// set inactive
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}
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return 1;
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}
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return 0;
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}
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/*---------------------------------------------------------------------------*/
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SENSORS_SENSOR(tmp102_sensor, "Temperature", value, configure, status); // register the functions
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