[PIC] Code to read temperature problem

hssn601 · Dec 19, 2013

Hi All,

i have developed a code to read temperature but its not working please help to correct it.

Sensor Model:am2315

Sensor info:

Code:

#include <18f4525.h>  
#include <stdlib.h>  
  
  
  
#fuses INTRC_IO, NOWDT, PUT , BROWNOUT, NOLVP, NOPROTECT, NOMCLR   
#use delay(clock=8000000) 
  
#use rs232(baud=9600, xmit=PIN_C6, rcv=PIN_C7, ERRORS) 
#use i2c(master, sda=PIN_C4, scl=PIN_C3, FORCE_HW)  
  

 unsigned char rx_byte,rx_byte1,rx_byte2,rx_byte3; 
  
  
void main(void)  
{  
  
   
   
SET_TRIS_A(0x00);  
 int a=0; 
  
while (a<2){  
   output_high(PIN_A1); 
    
   delay_ms(500);  
   output_low(PIN_A1);  
    
   delay_ms(100);  
   a++; 
}  
  
  
while (1)  
    {  
        printf ("Start i2c \n");  
        i2c_start();  
        delay_ms(50);  
        i2c_write(0xB8);  /* Device Address */ 
        
        i2c_write(0x03);  
      
          
           
          
        // reading humidity 
        rx_byte = i2c_read(0x00);  
     
          
        rx_byte1 = i2c_read(0x01);  
        
          
        
          
          
          
        //read temp 
        rx_byte2 = i2c_read(0x02);  
       
          
        rx_byte3 = i2c_read(0x03);  
        
          
        
        printf ("rx_byte1 = 0x%2.2X\r   0x%2.2X\r \n", rx_byte, rx_byte1);       
        printf ("rx_byte1 = 0x%2.2X\r   0x%2.2X\r \n", rx_byte2, rx_byte3);   
        
          
          
          
        
          
          
        i2c_stop();  
      
        printf ("End\n");  
    }  
  
  
  
  
}

babar_ali · Dec 19, 2013

Re: Connecting temperature sensor on i2c c18 and ccs

Hello

Why are you putting delays at the end of each command for I2C comunication i.e.

Code:

 i2c_start(); delay_ms(50);

. During the communication stop using printf. Once you are done with communication display results then. Also the what clock settings are you using for I2C? I cannot see that in above code.

Enjoy!

hssn601 · Dec 19, 2013

Re: Connecting temperature sensor on i2c c18 and ccs

babar_ali said:
Hello

Why are you putting delays at the end of each command for I2C comunication i.e.

Code:

i2c_start(); delay_ms(50);

. During the communication stop using printf. Once you are done with communication display results then. Also the what clock settings are you using for I2C? I cannot see that in above code.

Enjoy!

ok i got it actually i am using i2c 1st time can you tell me what clock settings i have to use.

thanks

jayanth.devarayanadurga · Dec 19, 2013

Re: Connecting temperature sensor on i2c c18 and ccs

mikroC Code not tested.

Code C - [expand]
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I2C1_Init(100000);         // initialize I2C communication
I2C1_Start();              // issue I2C start signal
I2C1_Wr(0xB8);             // send byte via I2C  (device address + W)
I2C1_Wr(0x03);                // send byte (address of EEPROM location)
I2C1_Wr(0x00);             // send data (data to be written)
I2C1_Wr(0x00);
I2C1_Stop();               // issue I2C stop signal
 
I2C1_Start();              // issue I2C start signal
I2C1_Wr(0xB9);             // send byte via I2C  (device address + W)
FC = I2C1_Rd(1);       // Read the data (acknowledge)
RN = I2C1_Rd(1);       // Read the data (acknowledge)
RHL = I2C1_Rd(1);       // Read the data (acknowledge)
RHH = I2C1_Rd(1);       // Read the data (acknowledge)
TEMPL = I2C1_Rd(1);       // Read the data (acknowledge)
TEMPH = I2C1_Rd(1);       // Read the data (acknowledge)
RHL = I2C1_Rd(1);       // Read the data (acknowledge)
RHH = I2C1_Rd(1);       // Read the data (acknowledge)
CRC = I2C1_Rd(1);       // Read the data (acknowledge)
I2C1_Stop();               // issue I2C stop signal

babar_ali · Dec 19, 2013

Re: Connecting temperature sensor on i2c c18 and ccs

hssn601 said:
ok i got it actually i am using i2c 1st time can you tell me what clock settings i have to use.

You must be aware of I2C protocol. I normally use 100Kb/s transfer rate. To do this you must read out the formula in microcontroller datasheet to set this rate. for pic18f25x i use the following function.

Code:

//some where in header file put these two 

#define FOSC 4000000
#define Baud 100000 

void I2Cinitilise(void)
{
	SSPCON1 = 0x28;	// I2C ENB, FOSC / (4 * (SSPADD+1)) 
	SSPADD = ((FOSC/4)/Baud)-1;
	SSPIF = 0;	
}

or you can read the manual for C18 and see how to set these clock rates.
Enjoy!!!

hssn601 · Dec 19, 2013

Re: Connecting temperature sensor on i2c c18 and ccs

jayanth.devarayanadurga said:
mikroC Code not tested.

why you have readed rhl and rhh twice.

Code:

RHL = I2C1_Rd(1);       // Read the data (acknowledge)
RHH = I2C1_Rd(1);       // Read the data (acknowledge)

and send

Code:

I2C1_Wr(0x00);             // send data (data to be written)
I2C1_Wr(0x00);

twice

jayanth.devarayanadurga · Dec 19, 2013

Re: Connecting temperature sensor on i2c c18 and ccs

It was a mistake. Mentio the PIC and Fosc you are using. I will compile a code and post it.

Code C - [expand]
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I2C1_Start();              // issue I2C start signal
I2C1_Wr(0xB9);             // send byte via I2C  (device address + W)
FC = I2C1_Rd(1);       // Read the data (acknowledge)
RN = I2C1_Rd(1);       // Read the data (acknowledge)
RHL = I2C1_Rd(1);       // Read the data (acknowledge)
RHH = I2C1_Rd(1);       // Read the data (acknowledge)
TEMPL = I2C1_Rd(1);       // Read the data (acknowledge)
TEMPH = I2C1_Rd(1);       // Read the data (acknowledge)
CRC = I2C1_Rd(1);       // Read the data (acknowledge)
I2C1_Stop();

hssn601 · Dec 19, 2013

Re: Connecting temperature sensor on i2c c18 and ccs

jayanth.devarayanadurga said:

It was a mistake. Mentio the PIC and Fosc you are using. I will compile a code and post it.

Code C - [expand]
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I2C1_Start();              // issue I2C start signal
I2C1_Wr(0xB9);             // send byte via I2C  (device address + W)
FC = I2C1_Rd(1);       // Read the data (acknowledge)
RN = I2C1_Rd(1);       // Read the data (acknowledge)
RHL = I2C1_Rd(1);       // Read the data (acknowledge)
RHH = I2C1_Rd(1);       // Read the data (acknowledge)
TEMPL = I2C1_Rd(1);       // Read the data (acknowledge)
TEMPH = I2C1_Rd(1);       // Read the data (acknowledge)
CRC = I2C1_Rd(1);       // Read the data (acknowledge)
I2C1_Stop();

i am using pic 24F16KA102 with ccs compailer

here is my code:

Code:

#include<24F16KA102.h>
#device ADC=10

#FUSES NOWDT                    //No Watch Dog Timer
#FUSES NOWRTB                   //Boot block not write protected
#FUSES NOBSS                    //No boot segment
#FUSES NOPROTECT                //Code not protected from reading
#FUSES NOWRT                    //Program memory not write protected
#FUSES FRC                      //Internal Fast RC Oscillator
#FUSES IESO                     //Internal External Switch Over mode enabled
#FUSES NOPR                     //Pimary oscillaotr disabled
#FUSES OSCIO                    //OSC2 is general purpose output
#FUSES POSCFREQ_H            
#FUSES SOSC_HIGH             
#FUSES NOCKSFSM                 //Clock Switching is disabled, fail Safe clock monitor is disabled
#FUSES WPOSTS16                 //Watch Dog Timer PostScalar 1:32768
//#FUSES WPRES128                 //Watch Dog Timer PreScalar 1:128
#FUSES WINDIS                   //Watch Dog Timer in non-Window mode
#FUSES NOBROWNOUT               //No brownout reset
#FUSES PUT                      //Power Up Timer
#FUSES BORV_LOW              
#FUSES MCLR                     //Master Clear pin enabled
#FUSES ICSP1                    //ICD uses PGC1/PGD1 pins
#FUSES NODEBUG                  //No Debug mode for ICD
#FUSES DSWDT2147483648       
#FUSES DSWDTCK_LPRC          
#FUSES RTCCK_SOSC            
#FUSES DSBOR                 
#FUSES DSWDT                 
#FUSES NOALTI2C                 //I2C mapped to alternate pins

#device ADC=10

#use delay(clock=8000000)
#opt 9

#use rs232(UART1,baud=9600,parity=N,bits=8,stream=sbuff)
#use i2c(Master,Fast,sda=PIN_B9,scl=PIN_B8,force_hw)//disable hardware i2c for sht15 as the library uses bit banging
#use standard_io(B)

#include <string.h>

#ZERO_RAM

static int tick100ms;


#int_TIMER1
void  TIMER1_isr(void) //100mSec overflow
{
   set_timer1( 0x3CB0 );

   tick100ms++;
   if( tick100ms == 10)
   {
      tick100ms=0;
      output_toggle(PIN_B15);
   }

}


void main()
{


   setup_timer1(TMR_INTERNAL | TMR_DIV_BY_8 ); 
   setup_wdt(WDT_OFF);
   enable_interrupts(INT_TIMER1);
   
   fprintf( sbuff, "\r\nBoot: OK\r\n\r\n");
 
 
  
   
    
   
 unsigned char fc,rn,rhl,rhh,templ,temph,crc;
   while(TRUE)
   {
      
      i2c_start(); // Issues a start command when in the I2C master mode.
 
      i2c_write(0xB8); // Sends a single byte over the I2C interface.
      i2c_write(0x03);
      i2c_write(0x00);
      i2c_write(0x00);
      
     i2c_stop(); //Issues a stop command when in the I2C master mode.
     
     delay_ms(100);
     
    I2C_Start();              // issue I2C start signal
    i2c_write(0xB9);             // send byte via I2C  (device address + W)
    FC = i2c_read(1);       // Read the data (acknowledge)
    RN = i2c_read(1);       // Read the data (acknowledge)
    RHL = i2c_read(1);       // Read the data (acknowledge)
    RHH = i2c_read(1);       // Read the data (acknowledge)
    TEMPL = i2c_read(1);       // Read the data (acknowledge)
    TEMPH = i2c_read(1);       // Read the data (acknowledge)
    CRC = i2c_read(1);  
      
      
     
     
 

     
     
     delay_ms(3000);        //delay 500 ms between reading to prevent self heating of sensor         
   }

}

jayanth.devarayanadurga · Dec 19, 2013

Re: Connecting temperature sensor on i2c c18 and ccs

This is compiled for 16 MHz external oscillator.

hssn601 · Dec 19, 2013

Re: Connecting temperature sensor on i2c c18 and ccs

jayanth.devarayanadurga said:
This is compiled for 16 MHz external oscillator.

ok i got it

- - - Updated - - -

jayanth.devarayanadurga said:
This is compiled for 16 MHz external oscillator.

i didnt get why you have writien these lines twice

Code:

RHL = I2C1_Read(1);       // Read the data (acknowledge)
RHH = I2C1_Read(1);       // Read the data (acknowledge)


I2C1_Write(0x00);

jayanth.devarayanadurga · Dec 19, 2013

Re: Connecting temperature sensor on i2c c18 and ccs

That was a mistake which happened while copying and pasting code. Remove two lines after this line.

Code C - [expand]
1
TEMPH = I2C1_Rd(1);       // Read the data (acknowledge)

The data is printed on UART1.

hssn601 · Dec 19, 2013

Re: Connecting temperature sensor on i2c c18 and ccs

jayanth.devarayanadurga said:
That was a mistake which happened while copying and pasting code. Remove two lines after this line.

Code C - [expand]
1
TEMPH = I2C1_Rd(1); // Read the data (acknowledge)

The data is printed on UART1.

and what about

Code:

 I2C1_Write(0x00);             // send data (data to be written)
     I2C1_Write(0x00);

actually i am using i2c first time thats why asking silly questions.

jayanth.devarayanadurga · Dec 19, 2013

Re: Connecting temperature sensor on i2c c18 and ccs

Page no. 10

Start + (I2C Addr + W) + Function code (0x03) + Start address (0x00) + Register number (0x00) + Stop

Start + (I2C Addr + R) + Continuously read Sensor data returned + Stop

https://github.com/adafruit/Adafruit_AM2315

Code C - [expand]
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void readDevice2(){
     I2C1_Start();              // issue I2C start signal
     I2C1_Write(0x5C);             // send byte via I2C  (device address + W)
     I2C1_Write(0x03);                // send byte (address of EEPROM location)
     I2C1_Write(0x00);             // send data (data to be written)
     I2C1_Write(0x04);
     I2C1_Stop();               // issue I2C stop signal
 
     I2C1_Start();              // issue I2C start signal
     I2C1_Write(0x5C);             // send byte via I2C  (device address + W)
     I2C1_Write(0x03);                // send byte (address of EEPROM location)
     I2C1_Write(0x00);             // send data (data to be written)
     I2C1_Write(0x04);
     I2C1_Stop();
     
     I2C1_Start();              // issue I2C start signal
     I2C1_Write(0x5C);             // send byte via I2C  (device address + W)
     dummy = I2C1_Read(1);       // Read the data (acknowledge)
     dummy = I2C1_Read(1);       // Read the data (acknowledge)
     FC = I2C1_Read(1);       // Read the data (acknowledge)
     RN = I2C1_Read(1);       // Read the data (acknowledge)
     RHL = I2C1_Read(1);       // Read the data (acknowledge)
     RHH = I2C1_Read(1);       // Read the data (acknowledge)
     TEMPL = I2C1_Read(1);       // Read the data (acknowledge)
     TEMPH = I2C1_Read(1);       // Read the data (acknowledge)
     I2C1_Stop();
 
     RH = RHH << 8;
     RH |= RHL;
 
     TEMP = TEMPH << 8;
     TEMP |= TEMPL;
 
}

hssn601 · Dec 19, 2013

Re: Connecting temperature sensor on i2c c18 and ccs

jayanth.devarayanadurga said:

Page no. 10

Start + (I2C Addr + W) + Function code (0x03) + Start address (0x00) + Register number (0x00) + Stop

Start + (I2C Addr + R) + Continuously read Sensor data returned + Stop

https://github.com/adafruit/Adafruit_AM2315

Code C - [expand]
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void readDevice2(){
     I2C1_Start();              // issue I2C start signal
     I2C1_Write(0x5C);             // send byte via I2C  (device address + W)
     I2C1_Write(0x03);                // send byte (address of EEPROM location)
     I2C1_Write(0x00);             // send data (data to be written)
     I2C1_Write(0x04);
     I2C1_Stop();               // issue I2C stop signal
 
     I2C1_Start();              // issue I2C start signal
     I2C1_Write(0x5C);             // send byte via I2C  (device address + W)
     I2C1_Write(0x03);                // send byte (address of EEPROM location)
     I2C1_Write(0x00);             // send data (data to be written)
     I2C1_Write(0x04);
     I2C1_Stop();
     
     I2C1_Start();              // issue I2C start signal
     I2C1_Write(0x5C);             // send byte via I2C  (device address + W)
     dummy = I2C1_Read(1);       // Read the data (acknowledge)
     dummy = I2C1_Read(1);       // Read the data (acknowledge)
     FC = I2C1_Read(1);       // Read the data (acknowledge)
     RN = I2C1_Read(1);       // Read the data (acknowledge)
     RHL = I2C1_Read(1);       // Read the data (acknowledge)
     RHH = I2C1_Read(1);       // Read the data (acknowledge)
     TEMPL = I2C1_Read(1);       // Read the data (acknowledge)
     TEMPH = I2C1_Read(1);       // Read the data (acknowledge)
     I2C1_Stop();
 
     RH = RHH << 8;
     RH |= RHL;
 
     TEMP = TEMPH << 8;
     TEMP |= TEMPL;
 
}

here is my code and uc is just sending FF

Code:

#include<24F16KA102.h>

#device ADC=10

#FUSES NOWDT                    //No Watch Dog Timer
#FUSES NOWRTB                   //Boot block not write protected
#FUSES NOBSS                    //No boot segment
#FUSES NOPROTECT                //Code not protected from reading
#FUSES NOWRT                    //Program memory not write protected
#FUSES FRC                      //Internal Fast RC Oscillator
#FUSES IESO                     //Internal External Switch Over mode enabled
#FUSES NOPR                     //Pimary oscillaotr disabled
#FUSES OSCIO                    //OSC2 is general purpose output
#FUSES POSCFREQ_H            
#FUSES SOSC_HIGH             
#FUSES NOCKSFSM                 //Clock Switching is disabled, fail Safe clock monitor is disabled
#FUSES WPOSTS16                 //Watch Dog Timer PostScalar 1:32768
//#FUSES WPRES128                 //Watch Dog Timer PreScalar 1:128
#FUSES WINDIS                   //Watch Dog Timer in non-Window mode
#FUSES NOBROWNOUT               //No brownout reset
#FUSES PUT                      //Power Up Timer
#FUSES BORV_LOW              
#FUSES MCLR                     //Master Clear pin enabled
#FUSES ICSP1                    //ICD uses PGC1/PGD1 pins
#FUSES NODEBUG                  //No Debug mode for ICD
#FUSES DSWDT2147483648       
#FUSES DSWDTCK_LPRC          
#FUSES RTCCK_SOSC            
#FUSES DSBOR                 
#FUSES DSWDT                 
#FUSES NOALTI2C                 //I2C mapped to alternate pins

#device ADC=10

#use delay(clock=8000000)
#opt 9

#use rs232(UART1,baud=9600,parity=N,bits=8,stream=sbuff)
#use i2c(Master,Fast,sda=PIN_B9,scl=PIN_B8,fast=100000,force_hw)//disable hardware i2c for sht15 as the library uses bit banging
#use standard_io(B)

#include <string.h>

#ZERO_RAM

static int tick100ms;


#int_TIMER1
void  TIMER1_isr(void) //100mSec overflow
{
   set_timer1( 0x3CB0 );

   tick100ms++;
   if( tick100ms == 10)
   {
      tick100ms=0;
      output_toggle(PIN_B15);
   }

}


void main()
{


   setup_timer1(TMR_INTERNAL | TMR_DIV_BY_8 ); 
   setup_wdt(WDT_OFF);
   enable_interrupts(INT_TIMER1);
   
   fprintf( sbuff, "\r\nSERIAL  OK !!\r\n\r\n");
 
 
  
   
    
   
 //unsigned char fc,rn,rhl,rhh,templ,temph,crc;
 
 unsigned CHAR FC, RN, RHL, RHH, TEMPL, TEMPH, CRC, RH, TEMP;
   while(TRUE)
   {
      
      ; // Issues a start command when in the I2C master mode.
 /*
      i2c_write(0xB8); // device address
      i2c_write(0x03); //function
      i2c_write(0x00);// reg address
      i2c_write(0x00);// start 
      */
      
     
     i2c_start();
      i2c_write(0xB8); // device address
      i2c_write(0x03); //function
      i2c_write(0x00);// reg address
      i2c_write(0x00);// start 
      
     i2c_stop();
     
     
     
    I2C_Start();              // issue I2C start signal
    i2c_write(0xB9);             // send byte via I2C  
    FC = i2c_read(1);       // Read the data (acknowledge)
    RN = i2c_read(1);       // Read the data (acknowledge)
    RHL = i2c_read(1);       // Read the data (acknowledge)
    RHH = i2c_read(1);       // Read the data (acknowledge)
    TEMPL = i2c_read(1);       // Read the data (acknowledge)
    TEMPH = i2c_read(1);       // Read the data (acknowledge)
    CRC = i2c_read(1);  
    
    
   
     
    
     
     i2c_stop();
            
            
            
            
      
   printf ("HL = 0x%2.2X HH= 0x%2.2X \rTEMPL = 0x%2.2X TEMPH= 0x%2.8X \r\r ",RHH,RHL,TEMPL,TEMPH);
   //printf ("TEMPL = 0x%2.2X TEMPH= 0x%2.2X \r ",TEMPL,TEMPH);
     
     
 

     
     
     delay_ms(3000);        //delay 500 ms to prevent heating of sensor         
   }

}

jayanth.devarayanadurga · Dec 19, 2013

Re: Connecting temperature sensor on i2c c18 and ccs

Try the code given in my last post.

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