print temperature: TODO 20130228 코드 정리/수정필요.

gistfile1.cpp

// TODO: pull 필요 없음! 
//      +--------+
//      |    ADD0+-------- GND
//      |TMP102  |   
//      |SCL  SDA|   
//      |--+--+--|
//         |  |
//     ----+--+----------- p27
//     -------+----------- p28
//       
// GND

#include "mbed.h"

int Tmp102_Test();

I2C i2c(p28, p27); // sda, scl

Serial pc(USBTX, USBRX);
int main() {
	Tmp102_Test(); // TMP102 test program.
}


int Tmp102_Test() {
    pc.printf("Tmp102 Test\n");
    
    char writedata[] = {0x00}; // Temperature Register's Pointer Register Byte is 0x00(p0=0, p1=0), So data is 0x00
    if(i2c.write(0x90, writedata, 1)) { // 0x90 is 8 bits representation of 0x48.
        pc.printf("Write failed\n");
    }

    int poll = 0;
    while(i2c.write(0x90, NULL, 0)) { // wait until we get an acknowledge
        poll++;
    }
    
    pc.printf("Chip acknowledged after %d polls\n", poll);

    pc.printf("Request temperature data:2bytes \n");

    char readdata[2];
    readdata[0] = 0;  
    readdata[1] = 0; 
    if(i2c.read(0x90, readdata, 2)) { // get temp data
        pc.printf("Read failed\n");
    }
   unsigned short data0 = readdata[0];
   unsigned short data1 = readdata[1];
   unsigned short res = (data0 << 4) | (data1 >> 4);    
   // unsigned short res = (readdata[0] << 4) | (readdata[1] >> 4); // overflow!
   float temp =  (float) ((float)res * 0.0625);
   pc.printf("Temperature: %f\n", temp);
}