JanPaul Bergeson / Mbed 2 deprecated All_Combined_Real

starting integration with XBee

Dependencies:   SDFileSystem mbed

temp_sensor.cpp@3:c611fff05072, 2016-03-15 (annotated)

Committer:
jphbergeson
Date:
Tue Mar 15 17:52:05 2016 +0000
Revision:
3:c611fff05072
Working with temp sensor

Who changed what in which revision?

UserRevisionLine numberNew contents of line
jphbergeson 3:c611fff05072 1 #include "temp_sensor.h"
jphbergeson 3:c611fff05072 2
jphbergeson 3:c611fff05072 3 /* MCP9808 high accuracy temp sensor from adafruit (no address pins pulled up) */
jphbergeson 3:c611fff05072 4 #define MCP9808_REG_TEMP (0x05) // Temperature Register
jphbergeson 3:c611fff05072 5 #define MCP9808_REG_CONF (0x01) // Configuration Register
jphbergeson 3:c611fff05072 6 #define MCP9808_ADDR (0x30) // MCP9808 base address 0x18<<1
jphbergeson 3:c611fff05072 7
jphbergeson 3:c611fff05072 8 I2C i2c(PTE25, PTE24);
jphbergeson 3:c611fff05072 9
jphbergeson 3:c611fff05072 10 char data_write[3];
jphbergeson 3:c611fff05072 11 char data_read[2];
jphbergeson 3:c611fff05072 12 int tempval;
jphbergeson 3:c611fff05072 13
jphbergeson 3:c611fff05072 14 volatile char TempCelsiusDisplay[] = "+abc.dd C";
jphbergeson 3:c611fff05072 15
jphbergeson 3:c611fff05072 16 void init_temp_sensor() {
jphbergeson 3:c611fff05072 17
jphbergeson 3:c611fff05072 18 wait(3);
jphbergeson 3:c611fff05072 19 i2c.frequency(10000); // default is 100000
jphbergeson 3:c611fff05072 20
jphbergeson 3:c611fff05072 21 /* Configure the Temperature sensor device MCP9808:
jphbergeson 3:c611fff05072 22 - Thermostat mode Interrupt not used
jphbergeson 3:c611fff05072 23 - Fault tolerance: 0
jphbergeson 3:c611fff05072 24 */
jphbergeson 3:c611fff05072 25 data_write[0] = MCP9808_REG_CONF;
jphbergeson 3:c611fff05072 26 data_write[1] = 0x00; // config msb
jphbergeson 3:c611fff05072 27 data_write[2] = 0x00; // config lsb
jphbergeson 3:c611fff05072 28 int status = i2c.write(MCP9808_ADDR, data_write, 3, 0);
jphbergeson 3:c611fff05072 29 if (status != 0) { // Error
jphbergeson 3:c611fff05072 30 // pc.printf(" error status = 0x%08x\r\n", status);
jphbergeson 3:c611fff05072 31 // while (1) {
jphbergeson 3:c611fff05072 32 // myled = !myled;
jphbergeson 3:c611fff05072 33 // wait(0.2);
jphbergeson 3:c611fff05072 34 // }
jphbergeson 3:c611fff05072 35 }
jphbergeson 3:c611fff05072 36
jphbergeson 3:c611fff05072 37 }
jphbergeson 3:c611fff05072 38
jphbergeson 3:c611fff05072 39 void check_temp() {
jphbergeson 3:c611fff05072 40 // Read temperature register
jphbergeson 3:c611fff05072 41 data_write[0] = MCP9808_REG_TEMP;
jphbergeson 3:c611fff05072 42 i2c.write(MCP9808_ADDR, data_write, 1, 1); // no stop
jphbergeson 3:c611fff05072 43 i2c.read(MCP9808_ADDR, data_read, 2, 0);
jphbergeson 3:c611fff05072 44
jphbergeson 3:c611fff05072 45 if(data_read[0] & 0xE0) {
jphbergeson 3:c611fff05072 46 data_read[0] = data_read[0] & 0x1F; // clear flag bits
jphbergeson 3:c611fff05072 47 }
jphbergeson 3:c611fff05072 48 if((data_read[0] & 0x10) == 0x10) {
jphbergeson 3:c611fff05072 49 data_read[0] = data_read[0] & 0x0F;
jphbergeson 3:c611fff05072 50 TempCelsiusDisplay[0] = '-';
jphbergeson 3:c611fff05072 51 tempval = 256 - (data_read[0] << 4) + (data_read[1] >> 4);
jphbergeson 3:c611fff05072 52 } else {
jphbergeson 3:c611fff05072 53 TempCelsiusDisplay[0] = '+';
jphbergeson 3:c611fff05072 54 tempval = (data_read[0] << 4) + (data_read[1] >> 4);
jphbergeson 3:c611fff05072 55 }
jphbergeson 3:c611fff05072 56
jphbergeson 3:c611fff05072 57 // fractional part (0.25°C precision)
jphbergeson 3:c611fff05072 58 if (data_read[1] & 0x08) {
jphbergeson 3:c611fff05072 59 if(data_read[1] & 0x04) {
jphbergeson 3:c611fff05072 60 TempCelsiusDisplay[5] = '7';
jphbergeson 3:c611fff05072 61 TempCelsiusDisplay[6] = '5';
jphbergeson 3:c611fff05072 62 } else {
jphbergeson 3:c611fff05072 63 TempCelsiusDisplay[5] = '5';
jphbergeson 3:c611fff05072 64 TempCelsiusDisplay[6] = '0';
jphbergeson 3:c611fff05072 65 }
jphbergeson 3:c611fff05072 66 } else {
jphbergeson 3:c611fff05072 67 if(data_read[1] & 0x04) {
jphbergeson 3:c611fff05072 68 TempCelsiusDisplay[5] = '2';
jphbergeson 3:c611fff05072 69 TempCelsiusDisplay[6] = '5';
jphbergeson 3:c611fff05072 70 }else{
jphbergeson 3:c611fff05072 71 TempCelsiusDisplay[5] = '0';
jphbergeson 3:c611fff05072 72 TempCelsiusDisplay[6] = '0';
jphbergeson 3:c611fff05072 73 }
jphbergeson 3:c611fff05072 74 }
jphbergeson 3:c611fff05072 75
jphbergeson 3:c611fff05072 76 // Integer part
jphbergeson 3:c611fff05072 77 TempCelsiusDisplay[1] = (tempval / 100) + 0x30;
jphbergeson 3:c611fff05072 78 TempCelsiusDisplay[2] = ((tempval % 100) / 10) + 0x30;
jphbergeson 3:c611fff05072 79 TempCelsiusDisplay[3] = ((tempval % 100) % 10) + 0x30;
jphbergeson 3:c611fff05072 80 }
jphbergeson 3:c611fff05072 81
jphbergeson 3:c611fff05072 82
jphbergeson 3:c611fff05072 83