Ronaldas G / Mbed 2 deprecated MLX90614 IR_Temp_Sensor (change address)

I have spent so much time looking into how to change the address of a MLX90614 sensor for use of multiple sensors, so I think it might be helpful to somebody.

Dependencies:   mbed

Fork of MLX90614 IR_Temp_Sensor (change address) by Ronaldas G

main.cpp@1:117cc19bbd83, 2016-03-05 (annotated)

Committer:
ronixas
Date:
Sat Mar 05 18:36:10 2016 +0000
Revision:
1:117cc19bbd83
Parent:
0:039f25b3de3e 
x

Who changed what in which revision?

UserRevisionLine numberNew contents of line
ronixas 0:039f25b3de3e 1 #include "mbed.h"
ronixas 0:039f25b3de3e 2
ronixas 0:039f25b3de3e 3
ronixas 0:039f25b3de3e 4 DigitalOut myled(LED1); //displays I2C wait
ronixas 0:039f25b3de3e 5
ronixas 0:039f25b3de3e 6 I2C i2c(p28,p27); //sda,scl
ronixas 0:039f25b3de3e 7 Serial pc(USBTX,USBRX); //serial usb config
ronixas 0:039f25b3de3e 8
ronixas 0:039f25b3de3e 9 bool ch,ch2,ch3;
ronixas 0:039f25b3de3e 10 float temp; //temperature in degrees C
ronixas 0:039f25b3de3e 11 char p1,p2;
ronixas 0:039f25b3de3e 12
ronixas 0:039f25b3de3e 13 /* Change MLX90614 address
ronixas 0:039f25b3de3e 14
ronixas 0:039f25b3de3e 15 1. clear old address
ronixas 0:039f25b3de3e 16 2. set new address
ronixas 0:039f25b3de3e 17 3. check if the change happenned
ronixas 0:039f25b3de3e 18 4. power cycle sensor (reconnect power)
ronixas 0:039f25b3de3e 19
ronixas 0:039f25b3de3e 20 */
ronixas 0:039f25b3de3e 21
ronixas 0:039f25b3de3e 22 int main() {
ronixas 0:039f25b3de3e 23 while (1) {
ronixas 0:039f25b3de3e 24
ronixas 0:039f25b3de3e 25 //----clear old address------------------
ronixas 0:039f25b3de3e 26
ronixas 0:039f25b3de3e 27 // make sure i2c is inactive
ronixas 0:039f25b3de3e 28 i2c.stop();
ronixas 0:039f25b3de3e 29 wait(0.1);
ronixas 0:039f25b3de3e 30 //send start bit
ronixas 0:039f25b3de3e 31 i2c.start();
ronixas 0:039f25b3de3e 32 // address the sensor using universal address 0x00 not its default 0x5A
ronixas 0:039f25b3de3e 33 ch = i2c.write(0x00); // last bit 0 indicates write
ronixas 0:039f25b3de3e 34 // prints if sensor acknowledges
ronixas 0:039f25b3de3e 35 if (!ch){ pc.printf("no ack\n"); }
ronixas 0:039f25b3de3e 36 else pc.printf("ack 0x00\n");
ronixas 0:039f25b3de3e 37 // write command
ronixas 0:039f25b3de3e 38 // EEPROM address. Datasheet says 0x0E BUT!!! accessing EEPROM requires ading 0x20. Hence, 0x2E
ronixas 0:039f25b3de3e 39 ch2 = i2c.write(0x2E);
ronixas 0:039f25b3de3e 40 // prints if sensor acknowledges
ronixas 0:039f25b3de3e 41 if (!ch2) pc.printf("no ack address location\n");
ronixas 0:039f25b3de3e 42 pc.printf("ack 0x0E\n");
ronixas 0:039f25b3de3e 43 // delete old address
ronixas 0:039f25b3de3e 44 // LSB
ronixas 0:039f25b3de3e 45 i2c.write(0x00);
ronixas 0:039f25b3de3e 46 // MSB
ronixas 0:039f25b3de3e 47 i2c.write(0x00);
ronixas 0:039f25b3de3e 48 // use CRC-8 calculator to obtain PEC bit http://www.sunshine2k.de/coding/javascript/crc/crc_js.html
ronixas 0:039f25b3de3e 49 // I send 2E0000 --> PEC 0x6F
ronixas 0:039f25b3de3e 50 ch3 = i2c.write(0x6F);
ronixas 0:039f25b3de3e 51 // prints if sensor acknowledges
ronixas 0:039f25b3de3e 52 if(!ch3) pc.printf("no PEC\n");
ronixas 0:039f25b3de3e 53 else pc.printf("PEC success\n");
ronixas 0:039f25b3de3e 54 // release the bus
ronixas 0:039f25b3de3e 55 i2c.stop();
ronixas 0:039f25b3de3e 56 wait(1);
ronixas 0:039f25b3de3e 57
ronixas 0:039f25b3de3e 58 //-----set new address----------------
ronixas 0:039f25b3de3e 59
ronixas 0:039f25b3de3e 60 // send start bit
ronixas 0:039f25b3de3e 61 i2c.start();
ronixas 0:039f25b3de3e 62 // send universal device address 0x00
ronixas 0:039f25b3de3e 63 i2c.write(0x00);
ronixas 0:039f25b3de3e 64 // prints if sensor acknowledges
ronixas 0:039f25b3de3e 65 if (!ch) pc.printf("no ack\n");
ronixas 0:039f25b3de3e 66 else pc.printf("ack\n");
ronixas 0:039f25b3de3e 67 // send EEPROM location for slave address
ronixas 0:039f25b3de3e 68 ch2 = i2c.write(0x2E);
ronixas 0:039f25b3de3e 69 // prints if sensor acknowledges
ronixas 0:039f25b3de3e 70 if (!ch2) pc.printf("no ack slave address location\n");
ronixas 0:039f25b3de3e 71 else pc.printf("ack 2\n");
ronixas 0:039f25b3de3e 72 //write new address anything between 0x0000 and 0x007F (default 0x5A, PEC 0xE1)
ronixas 0:039f25b3de3e 73 // LSB
ronixas 0:039f25b3de3e 74 i2c.write(0x04);
ronixas 0:039f25b3de3e 75 // MSB
ronixas 0:039f25b3de3e 76 i2c.write(0x00);
ronixas 0:039f25b3de3e 77 // send PEC calculated from CRC-8
ronixas 0:039f25b3de3e 78 // I send 2E0400 -> PEC 0x3B
ronixas 0:039f25b3de3e 79 i2c.write(0x3B);
ronixas 0:039f25b3de3e 80 // release the bus
ronixas 0:039f25b3de3e 81 i2c.stop();
ronixas 0:039f25b3de3e 82 wait(1);
ronixas 0:039f25b3de3e 83
ronixas 0:039f25b3de3e 84 //----read address to make sure it worked------------
ronixas 0:039f25b3de3e 85
ronixas 0:039f25b3de3e 86 // send start bit
ronixas 0:039f25b3de3e 87 i2c.start();
ronixas 0:039f25b3de3e 88 // send universal address
ronixas 0:039f25b3de3e 89 ch = i2c.write(0x00);
ronixas 0:039f25b3de3e 90 // prints if sensor acknowledges
ronixas 0:039f25b3de3e 91 if (!ch) pc.printf("no ack\n");
ronixas 0:039f25b3de3e 92 else pc.printf("ack\n");
ronixas 0:039f25b3de3e 93 // send EEPROM slave location address
ronixas 0:039f25b3de3e 94 ch2 = i2c.write(0x2E);
ronixas 0:039f25b3de3e 95 // send repeated start
ronixas 0:039f25b3de3e 96 i2c.start();
ronixas 0:039f25b3de3e 97 // send universal address 0x00 (seven bit) and use 1 as the eight bit -> 0x01
ronixas 0:039f25b3de3e 98 i2c.write(0x01); // last bit 1 indicates read request
ronixas 0:039f25b3de3e 99 // read LSB
ronixas 0:039f25b3de3e 100 p1 = i2c.read(1);
ronixas 0:039f25b3de3e 101 // read MSB
ronixas 0:039f25b3de3e 102 p2 = i2c.read(1);
ronixas 0:039f25b3de3e 103 // read PEC
ronixas 0:039f25b3de3e 104 i2c.read(0);
ronixas 0:039f25b3de3e 105 // release the bus
ronixas 0:039f25b3de3e 106 i2c.stop();
ronixas 0:039f25b3de3e 107 wait(0.1);
ronixas 0:039f25b3de3e 108 // print hex
ronixas 0:039f25b3de3e 109 pc.printf("0x%x%x\nMSB 0x%x, LSB 0x%x\n", p2, p1, p2, p1);
ronixas 0:039f25b3de3e 110 wait(10);
ronixas 0:039f25b3de3e 111
ronixas 0:039f25b3de3e 112 //-----now turn of the sensor for the change to take effect----do not access it without turning it off first!!!!-------
ronixas 0:039f25b3de3e 113 }
ronixas 0:039f25b3de3e 114 }