git.gag.com Git - fw/sdcc/blob - device/examples/ds390/i2c390/ds1621.c

   1 #include "i2clole.h"
   2 #include "ds1621.h"
   3
   4
   5
   6 float ReadDS1621(char address) {
   7   float temperature;
   8   signed char counter, slope;
   9
  10   int id=DS1621_ID + (address<<1);
  11
  12   while (!I2CReset()) {
  13     //fprintf (stderr, "I2C bus busy, retrying.\n");
  14   }
  15
  16   i2cTransmitBuffer[0]=0xac; // access config command
  17   i2cTransmitBuffer[1]=0x09; // mode (8=continuous, 9=one-shot)
  18   if (I2CSend(id, 2)) return -999;
  19
  20   i2cTransmitBuffer[0]=0xee; // start conversion command
  21   if (I2CSend(id, 1)) return -999;
  22
  23   do {
  24     i2cTransmitBuffer[0]=0xac; // access config command
  25     if (I2CSendReceive(id, 1, 1)) return -999;
  26   } while ((i2cReceiveBuffer[0]&0x80)==0); // wait for conversion done
  27
  28   i2cTransmitBuffer[0]=0xaa; // read temperature command
  29
  30   if (I2CSendReceive(id, 1, 1)) return -999;
  31   temperature=i2cReceiveBuffer[0];
  32   i2cTransmitBuffer[0]=0xa8; // read counter command
  33   if (I2CSendReceive(id, 1, 1)) return -999;
  34   counter=i2cReceiveBuffer[0];
  35
  36   i2cTransmitBuffer[0]=0xa9; // read slope command
  37   if (I2CSendReceive(id, 1, 1)) return -999;
  38   slope=i2cReceiveBuffer[0];
  39
  40   temperature=temperature - 0.25 +
  41     ((float)slope-(float)counter)/(float)slope;
  42   return temperature;
  43 }