Interfacing Arduino mega with load cell and TM7709 ADC

Projects Programming
1

Hey guys,
I'm having a problem connecting load cell to Arduino, so I was suggested to use ADC 24-bit
so I bought TM7709 and here's its code

//TM7709 24bit ADC module arduino sketch
//coldtears electronics

//default connection arduino UNO
//DRDY = 11
//ADIO = 12
//SCLK = 13


#define TM7710_DRDY        3          
#define TM7710_ADIO        4          
#define TM7710_ADIO_OUT()  DDRB|=1<<4     
#define TM7710_ADIO_IN()   DDRB&=~(1<<4)  
#define Set_TM7710_SCLK()  PORTB|=1<<5
#define Set_TM7710_ADIO()  PORTB|=1<<4
#define Clr_TM7710_SCLK()  PORTB&=~(1<<5)
#define Clr_TM7710_ADIO()  PORTB&=~(1<<4)

unsigned char x[3];
long Result;
float vref=4.89;

void TM7710_start(void)   
{
    Clr_TM7710_ADIO();
    delayMicroseconds(1);
    Clr_TM7710_SCLK();
    delayMicroseconds(1);
}

void TM7710_stop(void)    
{
    Clr_TM7710_ADIO();
    delayMicroseconds(1);
    Set_TM7710_SCLK();
    delayMicroseconds(1);
    Set_TM7710_ADIO();
    delayMicroseconds(1);
}
void TM7710_write(unsigned char dd)
{
    unsigned char i; 

    for(i=8;i>0;i--)
    {
        if(dd&0x80)
            Set_TM7710_ADIO();   
        else
            Clr_TM7710_ADIO();   
        
        delayMicroseconds(1);
        Set_TM7710_SCLK();       
        delayMicroseconds(1);
        Clr_TM7710_SCLK();      
        dd<<=1;                  
    }
}

unsigned char TM7710_read(void)
{
    unsigned char data=0,i; 

    for(i=0;i<8;i++)
    {
        Set_TM7710_SCLK();                   
        
        data=data<<1;                                  
        if((PINB&(1<<TM7710_ADIO))==(1<<TM7710_ADIO))  
        {
          data=data+1;
        }
        delayMicroseconds(1);
        Clr_TM7710_SCLK();
         delayMicroseconds(1);
    }
    return data;
}
void TM7710_Init()
{
   TM7710_ADIO_OUT();
   delay(100);
   TM7710_stop();
   TM7710_start();
   TM7710_write(0xBF);        
   TM7710_write(0x20);      //Gain=128
   //TM7710_write(0x00); //Gain=16
   TM7710_stop();      
}
void setup() 
{
DDRB|=1<<5 ;
delay(1000);
Serial.begin(57600);
Serial.println("TM7709 24bit ADC Module");
TM7710_Init();
}
    
void loop()
{  
   while((PINB&(1<<TM7710_DRDY))==(1<<TM7710_DRDY)); 
   TM7710_start();
   TM7710_write(0x7F);        
   TM7710_ADIO_IN();          
   for(unsigned char j=0;j<3;j++)
   {
   x[j]=TM7710_read();
   }
   TM7710_ADIO_OUT();         
   TM7710_stop();
   Result=x[0];
   Result = Result * 256;
   Result = Result + x[1];
   Result = Result * 256;
   Result = Result + x[2];
   Result = Result - 6912000;
   
   double volt = Result * vref /16 / 6912000; 
   printFloat(volt,6); 
   Serial.println(" V  ");

}


 void printFloat(float value, int places) {
 // this is used to cast digits
 int digit;
 float tens = 0.1;
 int tenscount = 0;
 int i;
 float tempfloat = value;

 // if value is negative, set tempfloat to the abs value

   // make sure we round properly. this could use pow from
 //<math.h>, but doesn't seem worth the import
 // if this rounding step isn't here, the value  54.321 prints as

 // calculate rounding term d:   0.5/pow(10,places)
 float d = 0.5;
 if (value < 0)
   d *= -1.0;
 // divide by ten for each decimal place
 for (i = 0; i < places; i++)
   d/= 10.0;
 // this small addition, combined with truncation will round our

 tempfloat +=  d;

 if (value < 0)
   tempfloat *= -1.0;
 while ((tens * 10.0) <= tempfloat) {
   tens *= 10.0;
   tenscount += 1;
 }

 // write out the negative if needed
 if (value < 0)
   Serial.print('-');

 if (tenscount == 0)
   Serial.print(0, DEC);

 for (i=0; i< tenscount; i++) {
   digit = (int) (tempfloat/tens);
   Serial.print(digit, DEC);
   tempfloat = tempfloat - ((float)digit * tens);
   tens /= 10.0;
 }

 // if no places after decimal, stop now and return
 if (places <= 0)
   return;

 // otherwise, write the point and continue on
 Serial.print('.');

 for (i = 0; i < places; i++) {
   tempfloat *= 10.0;
   digit = (int) tempfloat;
   Serial.print(digit,DEC);
   // once written, subtract off that digit
   tempfloat = tempfloat - (float) digit;
 }
 
  }

and here's how to connect it

but I got nothing , any help
p.s : I'm working on Labview interface

Thanks

2

You need to separate your problem into several parts.

Can you commuicate with the adc ?

Is the adc working ?

Is the load cell and its amplifier working ?

If you are not getting a reading, there could be several things wrong. If you are uncertain the load cell is working, try connecting something very simple, like a straightforward variable resistor (pot) or a 3.3V source, to the adc, and see if you can read that.

3

I don't know what that communication scheme is. However, your first post says mega and the top of the sketch says Uno. You should be wary of the pin numbering when you get someone else's Uno sketch and try to run it on a mega.

4

Something odd about an IC for which the datasheet is only available from a bunch of malware-infested secondary sources and not the maker.