Diff: N5110.cpp

Revision:

20:4145b7a59ef7

Parent:

19:ba8addc061ea

--- a/N5110.cpp	Thu Apr 23 18:57:52 2015 +0000
+++ b/N5110.cpp	Thu May 07 16:12:53 2015 +0000
@@ -4,8 +4,10 @@
 @brief Member functions implementations
 
 */
+
+#include "N5110.h"
 #include "mbed.h"
-#include "N5110.h"
+#include "BMP180.h"
 
 
 N5110::N5110(PinName pwrPin, PinName scePin, PinName rstPin, PinName dcPin, PinName mosiPin, PinName sclkPin, PinName ledPin)
@@ -404,3 +406,317 @@
     }
 
 }
+
+
+
+BMP180::BMP180(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(LED4,LED3,LED2,LED1);
+}
+
+Measurement BMP180::readValues()
+{
+    // algorithm for taking measurement is taken from datasheet
+    int32_t UT = readUncompensatedTemperatureValue();
+    int32_t UP = readUncompensatedPressureValue();
+    // once you have the uncompensated T and P, you can calculate the true T and P
+    // using the equations from the datasheet
+    int32_t T = calcTrueTemperature(UT);
+    int32_t P = calcTruePressure(UP);
+
+    Measurement measurement;
+    measurement.temperature = T*0.1;  // scaled by 0.1 C
+    measurement.pressure = P*0.01;    // Put pressure in mb
+
+    return measurement;
+}
+
+int32_t BMP180::readUncompensatedTemperatureValue()
+{
+    // from algorithm in datasheet - p15
+    sendByteToRegister(0x2E,0xF4);
+    wait_ms(5);  // 4.5 ms delay for OSS = 1
+    char MSB = readByteFromRegister(0xF6);
+    char LSB = readByteFromRegister(0xF7);
+    // combine in 16-bit value
+    int UT = (MSB << 8) | LSB;
+#ifdef DEBUG
+    UT = 27898;  // test data from datasheet
+    printf("****DEBUG MODE****\nUT = %d\n",UT);
+#endif
+    return UT;
+}
+
+int32_t BMP180::readUncompensatedPressureValue()
+{
+    // from datasheet
+    char byte = 0x34 + (oss << 6);
+    sendByteToRegister(byte,0xF4);
+    wait_ms(8);  // 7.5 ms delay for OSS = 1
+
+    char MSB = readByteFromRegister(0xF6);
+    char LSB = readByteFromRegister(0xF7);
+    char XLSB = readByteFromRegister(0xF7);
+    int UP = (MSB << 16 | LSB << 8 | XLSB) >> (8 - oss);
+
+#ifdef DEBUG
+    UP = 23843;   // test data from datasheet
+    printf("UP = %d\n",UP);
+#endif
+    return UP;
+}
+
+int32_t BMP180::calcTrueTemperature(int32_t UT)
+{
+    // equations from data sheet
+    X1 = ((UT - calibration.AC6)*calibration.AC5) >> 15;
+    X2 = (calibration.MC << 11) / (X1 + calibration.MD);
+    B5 = X1 + X2;
+    int32_t T = (B5 + 8) >> 4;
+#ifdef DEBUG
+    printf("****\nX1=%d\nX2=%d\nB5=%d\nT=%d\n",X1,X2,B5,T);
+#endif
+    return T;
+}
+
+int32_t BMP180::calcTruePressure(int32_t UP)
+{
+    // equations from data sheet
+    B6 = B5 - 4000;
+    X1 = (calibration.B2 * ((B6*B6) >> 12))>>11;
+    X2 = (calibration.AC2*B6)>>11;
+    X3 = X1 + X2;
+    B3 = (((calibration.AC1*4 + X3) << oss)+2)/4;
+#ifdef DEBUG
+    printf("*****\nB6=%d\nX1=%d\nX2=%d\nX3=%d\nB3=%d\n",B6,X1,X2,X3,B3);
+#endif
+    X1 = (calibration.AC3*B6)>>13;
+    X2 = (calibration.B1*((B6*B6)>>12))>>16;
+    X3 = ((X1+X2)+2)/4;
+    B4 = (calibration.AC4*(uint32_t)(X3+32768))>>15;
+#ifdef DEBUG
+    printf("X1=%d\nX2=%d\nX3=%d\nB4=%u\n",X1,X2,X3,B4);
+#endif
+    B7 = ((uint32_t)UP - B3)*(50000>>oss);
+#ifdef DEBUG
+    printf("B7=%u\n",B7);
+#endif
+    int32_t P;
+    if (B7 < 0x80000000)
+        P = (B7*2)/B4;
+    else
+        P = (B7/B4)*2;
+#ifdef DEBUG
+    printf("P=%d\n",P);
+#endif
+    X1 = (P>>8)*(P>>8);
+#ifdef DEBUG
+    printf("X1=%d\n",X1);
+#endif
+    X1 = (X1*3038)>>16;
+#ifdef DEBUG
+    printf("X1=%d\n",X1);
+#endif
+    X2 = (-7357*P)>>16;
+#ifdef DEBUG
+    printf("X2=%d\n",X2);
+#endif
+    P = P + (X1+X2+3791)/16;
+#ifdef DEBUG
+    printf("P=%d\n",P);
+#endif
+
+    return P;
+
+}
+
+// configure the barometer
+void BMP180::init()
+{
+    i2c->frequency(400000); // set Fast Mode I2C frequency
+
+    char data = readByteFromRegister(ID_REG);  // Section 4 - datasheet
+    if (data != 0x55) { // if correct ID not found, hang and flash error message
+        error();
+    }
+
+    readCalibrationData();
+
+    oss = 1;  // standard power oversampling setting
+
+#ifdef DEBUG
+    oss = 0;  // used when testing data sheet example
+#endif
+
+
+}
+
+// Reads factory calibrated data
+void BMP180::readCalibrationData()
+{
+
+    char eeprom[22];
+
+    readBytesFromRegister(EEPROM_REG_ADD,22,eeprom);
+    // store calibration data in structure
+    calibration.AC1 = (int16_t) (eeprom[0] << 8) | eeprom[1];
+    calibration.AC2 = (int16_t) (eeprom[2] << 8) | eeprom[3];
+    calibration.AC3 = (int16_t) (eeprom[4] << 8) | eeprom[5];
+    calibration.AC4 = (uint16_t) (eeprom[6] << 8) | eeprom[7];
+    calibration.AC5 = (uint16_t) (eeprom[8] << 8) | eeprom[9];
+    calibration.AC6 = (uint16_t) (eeprom[10] << 8) | eeprom[11];
+    calibration.B1 = (int16_t) (eeprom[12] << 8) | eeprom[13];
+    calibration.B2 = (int16_t) (eeprom[14] << 8) | eeprom[15];
+    calibration.MB = (int16_t) (eeprom[16] << 8) | eeprom[17];
+    calibration.MC = (int16_t) (eeprom[18] << 8) | eeprom[19];
+    calibration.MD = (int16_t) (eeprom[20] << 8) | eeprom[21];
+
+    // test data from data sheet
+#ifdef DEBUG
+    calibration.AC1 = 408;
+    calibration.AC2 = -72;
+    calibration.AC3 = -14383;
+    calibration.AC4 = 32741;
+    calibration.AC5 = 32757;
+    calibration.AC6 = 23153;
+    calibration.B1 = 6190;
+    calibration.B2 = 4;
+    calibration.MB = -32768;
+    calibration.MC = -8711;
+    calibration.MD = 2868;
+    printf("****EXAMPLE CALIBRATION DATA****\n");
+    printf("AC1=%d\nAC2=%d\nAC3=%d\nAC4=%u\nAC5=%u\nAC6=%u\nB1=%d\nB2=%d\nMB=%d\nMC=%d\nMD=%d\n",
+           calibration.AC1,calibration.AC2,calibration.AC3,calibration.AC4,calibration.AC5,calibration.AC6,
+           calibration.B1,calibration.B2,calibration.MB,calibration.MC,calibration.MD);
+#endif
+}
+
+
+// reads a byte from a specific register
+char BMP180::readByteFromRegister(char reg)
+{
+    int nack = i2c->write(BMP180_W_ADDRESS,&reg,1,true);  // send the register address to the slave
+    if (nack)
+        error();  // if we don't receive acknowledgement, flash error message
+
+    char rx;
+    nack = i2c->read(BMP180_W_ADDRESS,&rx,1);  // read a byte from the register and store in buffer
+    if (nack)
+        error();  // if we don't receive acknowledgement, flash error message
+
+    return rx;
+}
+
+// reads a series of bytes, starting from a specific register
+void BMP180::readBytesFromRegister(char reg,int numberOfBytes,char bytes[])
+{
+    int nack = i2c->write(BMP180_W_ADDRESS,&reg,1,true);  // send the slave write address and the configuration register address
+
+    if (nack)
+        error();  // if we don't receive acknowledgement, flash error message
+
+    nack = i2c->read(BMP180_W_ADDRESS,bytes,numberOfBytes);  // read bytes
+    if (nack)
+        error();  // if we don't receive acknowledgement, flash error message
+
+}
+
+// sends a byte to a specific register
+void BMP180::sendByteToRegister(char byte,char reg)
+{
+    char data[2];
+    data[0] = reg;
+    data[1] = byte;
+    // send the register address, followed by the data
+    int nack = i2c->write(BMP180_W_ADDRESS,data,2);
+    if (nack)
+        error();  // if we don't receive acknowledgement, flash error message
+
+}
+
+void BMP180::error()
+{
+    while(1) {
+        leds->write(15);
+        wait(0.1);
+        leds->write(0);
+        wait(0.1);
+    }
+}
+
+
+
+
+N5110 lcd(p7,p8,p9,p10,p11,p13,p26);//The ports  being connected of the mbed
+BusOut leds(LED4,LED3,LED2,LED1);//The ports  being connected of the LCD
+BMP180 bmp180(p28,p27);//The ports being connected to the sensor
+Serial serial(USBTX,USBRX);//Timer set-up tool
+
+
+//Define the variable
+void serialISR();//ISR that is called when serial data is received
+void setTime();// function to set the UNIX time
+int setTimerFlag = 0;// flag for ISR
+char rxString[16];//Create a 16 chars row to display the data
+
+int main()
+{
+    lcd.init();
+    bmp180.init();//Display the word before the sensor data
+    lcd.printString("Weather",0,0);//At the location (0,0),display word "Weather"
+    lcd.printString("Station",1,3);//At the location (1,3),display word "Station"
+    wait(2.0);//The word above stay for 2s
+    lcd.clear();//Clean the display for the continued work
+  
+    Measurement measurement;
+
+    serial.attach(&serialISR);//attach serial ISR
+    char t[30];//Create a 30 chars row to display the time
+    while(1) {
+
+        time_t seconds = time(NULL);//get current time
+        // format time into a string (time and date)
+        strftime(t, 30 , "%X %D",localtime(&seconds));//
+        // print over serial
+        serial.printf("Time = %s\n" ,t);//Display the timer
+        lcd.printString(t,0,5);//The location of the timer
+
+        if(setTimerFlag) {// if updated time has been sent
+            setTimerFlag = 0;//clear flag
+            setTime();// update time
+
+        }
+
+        measurement = bmp180.readValues();//
+        char T[14];//Create a 14 chars row to display the temperature
+        int length =sprintf(T,"T = %.2f C",measurement.temperature);//Set up "T = sensor data" as the thing will be shown
+        if (length <= 14)//Judge the length of chars
+        lcd.printString(T,0,1);//The location of the T will be shown
+        char P[14];//Create a 14 chars row to display the pressure
+        length = sprintf(P,"P = %.2f mb",measurement.pressure);//Set up "P = sensor data" as the thing will be shown
+        lcd.printString(P,0,3); //The location of the P will be shown
+        wait(1);//Repeat the circulate each 1s
+        lcd.clear();  //Clear the data for next processing
+    }     
+}
+
+
+void setTime()//// print time for debugging
+{
+     
+    serial.printf("set_time - %s",rxString);
+    //// atoi() converts a string to an integer
+    int time = atoi(rxString);
+    //update the time
+    set_time(time);
+}
+
+void serialISR()// when a serial interrupt occurs, read rx string into buffer
+{   
+    
+    serial.gets(rxString,16);
+    //// set flag
+    setTimerFlag = 1;
+}