temp: [#61] Communication with sensor.

* Up/Down state.
* Raw temperature data.
* Can't believe it actually worked.

source/shoh/src/threads/temperature/SensorTempSHT20.cpp

@@ -28,11 +28,56 @@
 
 
 SensorTempSHT20::SensorTempSHT20(I2C* pi2c)
-: _pi2c(pi2c), _dev_addr(0x40)
-{}
+: _pi2c(pi2c), _dev_addr(0x40), _up_flag(false),
+_com_read_hold(0xe3), _com_read_nohold(0xf3),
+_com_write_ur(0xe6), _com_read_ur(0xe7),
+_com_soft_reset(0xfe)
+{
+  this->read();
+}
 
 SensorTempSHT20::~SensorTempSHT20()
 {}
+
+int8_t SensorTempSHT20::getTemperature()
+{
+  uint16_t raw_temp = this->read();
+  bool err_bit = raw_temp & 0x1;
+  if (err_bit)
+    return -128;
+  
+  //TODO: Temperature parsing has to be done here.
+  return raw_temp >> 9;
+}
+
+bool SensorTempSHT20::is_up()
+{
+  this->read();
+  return this->_up_flag;
+}
+
+uint16_t SensorTempSHT20::read()
+{
+  uint8_t  tbuf = this->_com_read_hold;
+  uint8_t  rbuf[3] = {0x0, 0x2, 0x0};
+  uint8_t crc = 0x0;
+  uint16_t  raw_temp = 0;
+  this->_up_flag = this->_pi2c->transaction(this->_dev_addr, &tbuf, 1, rbuf, 3);
+  
+  //Sensor changes this bit to 0 on temp measurement.
+  if (rbuf[1] & 0x2)
+    return 0x1;
+
+  raw_temp |= (rbuf[0] << 8);
+  raw_temp |= (rbuf[1] & 0xfc);
+  crc = rbuf[2];
+  LOG_WARNING("Raw data: %04x; CRC: %x", raw_temp, crc);
+
+  //TODO: crc check here.
+
+  return raw_temp;
+}
+
 /*
 const int16_t POLYNOMIAL = 0x131;
 

source/shoh/src/threads/temperature/SensorTempSHT20.h

@@ -12,17 +12,21 @@
 
 class SensorTempSHT20 {
 public:
-	SensorTempSHT20(I2C* pi2c);
-	virtual ~SensorTempSHT20();
+  SensorTempSHT20(I2C* pi2c);
+  virtual ~SensorTempSHT20();
+  int8_t getTemperature();
+  bool is_up();
 private:
-	uint16_t read();
+  uint16_t read();
 
-	bool write_com(uint8_t com, uint8_t *trdata, const uint16_t size);
-	bool read_com(uint8_t com, uint8_t *rdata, uint16_t size);
-
-	I2C* _pi2c;
-	const uint8_t _dev_addr;
-	bool _up_flag;
+  I2C* _pi2c;
+  const uint8_t _dev_addr;
+  bool _up_flag;
+  const uint8_t _com_read_hold;
+  const uint8_t _com_read_nohold;
+  const uint8_t _com_write_ur; //user register
+  const uint8_t _com_read_ur; //user register
+  const uint8_t _com_soft_reset;
 };
 
 #endif /* THREADS_TEMPERATURE_SENSORTEMPSHT20_H_ */

source/shoh/src/threads/temperature/Temperature.cpp

@@ -5,7 +5,8 @@
  */
 
 #include "Temperature.h"
-#include "SensorTempTC74.h"
+//#include "SensorTempTC74.h"
+#include "SensorTempSHT20.h"
 #include "Event.h"
 #include "Log.h"
 
@@ -15,7 +16,8 @@ Temperature::~Temperature() {}
 
 void Temperature::taskFunction()
 {
-	SensorTempTC74 ext_temp_sensor(this->_pi2c, 0x4a);
+	//SensorTempTC74 ext_temp_sensor(this->_pi2c, 0x4a);
+	SensorTempSHT20 ext_temp_sensor(this->_pi2c);
 	Event t (Event::ExternalTemp, -128);
 	int8_t temp_value = -128;
 	_qm->send<Event>(ThreadCommon::QueueManager::master_event_all, &t, 0);