first commit

libraries/Crowbits_DHT20/Crowbits_DHT20.cpp

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+#include <Crowbits_DHT20.h>
+
+
+Crowbits_DHT20::Crowbits_DHT20(TwoWire * pWire,uint8_t address)
+  : _pWire(pWire) {
+  _address = address;
+}
+
+int Crowbits_DHT20::begin() {
+  uint8_t readCMD[3]={0x71};
+  uint8_t data;
+  delay(100);
+  //_pWire->begin(14, 12);
+  //check if the IIC communication works 
+  writeCommand(readCMD,1);
+  
+  readData(&data, 1);
+  //Serial.println(data);
+  if((data | 0x8) == 0){
+     return 1;
+  }
+  if(data == 255) return 1;
+  return 0;
+}
+
+int Crowbits_DHT20::getTemperature() {
+  uint8_t readCMD[3]={0xac,0x33,0x00};
+  uint8_t data[6] = {0};
+  int retries = 10;
+  int temperature;
+  // when the returned data is wrong, request to get data again until the data is correct. 
+  writeCommand(readCMD, 3);
+  while(retries--) {
+    delay(10);
+    readData(data,6);
+    if((data[0] >> 7) == 0){
+      // DBG("bus not busy");
+       break;
+    }
+  }
+  uint32_t temp = data[3] & 0xff;
+  uint32_t temp1 = data[4] & 0xff;
+  uint32_t rawData = 0;
+  rawData = ((temp&0xf)<<16)+(temp1<<8)+(data[5]);
+  //DBG(rawData);
+  //DBG((temp&0xf)<<16);
+  temperature = (int)rawData/5242 -50;
+  //DBG(temperature)
+  return temperature;
+}
+
+int Crowbits_DHT20::getHumidity() {
+  uint8_t readCMD[3]={0xac,0x33,0x00};
+  uint8_t data[6] = {0};
+  int retries = 10;
+  float humidity_f;
+  int humidity_i;
+  // when the returned data is wrong, request to get data again until the data is correct. 
+  writeCommand(readCMD, 3);
+  while(retries--) {
+    delay(10);
+    readData(data,6);
+    if((data[0] >> 7) == 0){
+       //DBG("bus not busy");
+       break;
+    }
+  }
+  uint32_t temp = data[1] & 0xff;
+  uint32_t temp1 = data[2] & 0xff;
+  uint32_t rawData = 0;
+  rawData = (temp<<12)+(temp1<<4)+((data[3]&0xf0)>>4);
+  //DBG(rawData);
+  //DBG(temp<<12);
+  humidity_f = (float)rawData/0x100000;
+  humidity_i = (int)(humidity_f*100);
+  //DBG(humidity)
+  return humidity_i;
+}
+void Crowbits_DHT20::writeCommand(const void *pBuf, size_t size) {
+  if (pBuf == NULL) {
+   // DBG("pBuf ERROR!! : null pointer");
+  }
+
+  uint8_t * _pBuf = (uint8_t *)pBuf;
+  _pWire->beginTransmission(_address);
+  for (uint8_t i = 0; i < size; i++) {
+    
+    _pWire->write(_pBuf[i]);
+    
+  }
+  _pWire->endTransmission();
+}
+
+uint8_t Crowbits_DHT20::readData(void *pBuf, size_t size) {
+  delay(10);
+  if (pBuf == NULL) {
+   // DBG("pBuf ERROR!! : null pointer");
+  }
+  uint8_t * _pBuf = (uint8_t *)pBuf;
+  //read the data returned by the chip
+  _pWire->requestFrom(_address, size);
+  //uint8_t i = 0;
+  for (uint8_t i = 0 ; i < size; i++) {
+    _pBuf[i] = _pWire->read();
+   // DBG(_pBuf[i]);
+  }
+  return 1;
+  
+}