SparkFun Forums

[Programability]

Currently I'm trying to set up a multi-node thermostat system to try and better conserve energy and more importantly lower utility bill and add some other useful sensors and fancy electronics, which I'll explain later but right now I'm at a bit of a hang up on the basic and initial part.

I have an RHT03 and I'm trying to get it to read out correctly using a FreeSoC mini board, so far I have gotten EVERYTHING to work correctly with the exception of 2 things, the 1st is the negative values, I don't have a way on hand to make the sensor try to read negative tempuratures, the second is the main issue even though my RH and TMP readings are good my checksums do NOT match up, and I'm not sure what I have done wrong.

Code: Select all

/* ========================================
 *
 * Copyright YOUR COMPANY, THE YEAR
 * All Rights Reserved
 * UNPUBLISHED, LICENSED SOFTWARE.
 *
 * CONFIDENTIAL AND PROPRIETARY INFORMATION
 * WHICH IS THE PROPERTY OF your company.
 *
 * ========================================
*/
#include <project.h>
#include <BitCheck.h>

uint8 URh, LRh,UTmp, LTmp;
int Cs;

int16 Rh8, TmpC8, TmpF8, Rh16, TmpC16, TmpF16, CCS, RH, TMP;

int main()
{
    /* Place your initialization/startup code here (e.g. MyInst_Start()) */
    
    Clock_1_Enable();       //Enable Comm_poll clock set for 10KHz
    Comm_Poll_Start();      //Start PWM Comm_Poll to hold high for 2sec and low for 1ms
    
    Display_Start();        //Start UART with only TX (since thats all I care about ATM)
    
    BitClock_Enable();      //Enable Block at 1MHz to be used with LowBitTimer/DataBits/CommStart 
                            //to filter sort the different pulse lengths
    LowBitTimer_Start();    //Detects pulses under 30ms
    DataBits_Start();       //Detects all pulses
    CommStart_Start();      //Detects on a very brief pulse at start of RHT03 signal
    
    
    UpperRh_Start();        //Start Relative humiditys upeer 8-bit shift register
    LowerRh_Start();        //RH lower 8-bit shift register
    UpperTmp_Start();       //Start Tempurature upper 8-bit shift register
    LowerTmp_Start();       //TMP lower 8-bit shift register
    CheckSum_Start();       //Start Checksum 8-bit shift register
    RH_Start();             //Start Relative humiditys 16-bit shift register
    TMP_Start();            //Start Temperature 16-bit shift register
    
    //CyGlobalIntEnable;  /* Uncomment this line to enable global interrupts. */
            
    for(;;)
    {
        URh=UpperRh_ReadRegValue();         //read RH upper 8-bit
        LRh=LowerRh_ReadRegValue();         //read RH lower 8-bit
        UTmp=UpperTmp_ReadRegValue();       //read TMP upper 8-bit
        LTmp=LowerTmp_ReadRegValue();       //read TMP lower 8-bit
        Cs=CheckSum_ReadRegValue();         //read checksum 8-bit
        RH=RH_ReadRegValue();               //read RH 16-bit 
        TMP=TMP_ReadRegValue();             //read TMP 16-bit
        
        Rh8=URh+LRh;                        //8-bit RH = upper + lower
        TmpC8=UTmp+LTmp;                    //8-bit TMP(celsius) = upper + lower
        TmpF8=((TmpC8/10)*9/5+32)*10;       //8-bit TMP(farheniet) = conversion equation
        Rh16=RH;                            //16-bit RH = its register
        TmpC16=TMP;                         //16-bit TMP = its register
        TmpF16=((TmpC16/10)*9/5+32)*10;     //same conversion equation just for 16bit
        CCS=(URh+LRh+UTmp+LTmp);            //Checksum validation each 8-bit value added together
        
        Display_PutChar((URh/100)+48);                     //just my way of getting character 
                                                                             //output from an integer
        Display_PutChar(((URh/10)-(URh/100)*10)+48);
        Display_PutChar(((URh/1)-(URh/10)*10)+48);        
        
        Display_PutString(",");                            //delimiters
        Display_PutChar((LRh/100)+48);
        Display_PutChar(((LRh/10)-(LRh/100)*10)+48);
        Display_PutChar(((LRh/1)-(LRh/10)*10)+48);
        
        Display_PutString(",");
        Display_PutChar((UTmp/100)+48);
        Display_PutChar(((UTmp/10)-(UTmp/100)*10)+48);
        Display_PutChar(((UTmp/1)-(UTmp/10)*10)+48);
        
        
        Display_PutString(",");
        Display_PutChar((LTmp/100)+48);
        Display_PutChar(((LTmp/10)-(LTmp/100)*10)+48);
        Display_PutChar(((LTmp/1)-(LTmp/10)*10)+48);
                
        Display_PutString(",");
        Display_PutChar((Cs/100)+48);
        Display_PutChar(((Cs/10)-(Cs/100)*10)+48);
        Display_PutChar(((Cs/1)-(Cs/10)*10)+48);
        Display_PutCRLF(0);
        
        Display_PutString("                ");            //makes the calculated checksum
                                                                    //appear below captured
        Display_PutChar((CCS/100)+48);
        Display_PutChar(((CCS/10)-(CCS/100)*10)+48);
        Display_PutChar(((CCS/1)-(CCS/10)*10)+48);
        Display_PutCRLF(0);
        
        Display_PutString("Rh ");                          // display RH as a precision value
        Display_PutChar((Rh16/100)+48);
        Display_PutChar(((Rh16/10)-(Rh16/100)*10)+48);
        Display_PutString(".");
        Display_PutChar(((Rh16/1)-(Rh16/10)*10)+48);
        Display_PutString("%");
        Display_PutCRLF(0);
        
        Display_PutChar((TmpC16/100)+48);
        Display_PutChar(((TmpC16/10)-(TmpC16/100)*10)+48);
        Display_PutString(".");
        Display_PutChar(((TmpC16/1)-(TmpC16/10)*10)+48);
        Display_PutString("C/");
        Display_PutChar((TmpF16/100)+48);
        Display_PutChar(((TmpF16/10)-(TmpF16/100)*10)+48);
        Display_PutString(".");
        Display_PutChar(((TmpF16/1)-(TmpF16/10)*10)+48);
        Display_PutString("F");
        Display_PutCRLF(0);
                 
        Display_PutString("Rh ");
        Display_PutChar((Rh8/100)+48);
        Display_PutChar(((Rh8/10)-(Rh8/100)*10)+48);
        Display_PutString(".");
        Display_PutChar(((Rh8/1)-(Rh8/10)*10)+48);
        Display_PutString("%");
        Display_PutCRLF(0);
        
        Display_PutChar((TmpC8/100)+48);
        Display_PutChar(((TmpC8/10)-(TmpC8/100)*10)+48);
        Display_PutString(".");
        Display_PutChar(((TmpC8/1)-(TmpC8/10)*10)+48);
        Display_PutString("C/");
        Display_PutChar((TmpF8/100)+48);
        Display_PutChar(((TmpF8/10)-(TmpF8/100)*10)+48);
        Display_PutString(".");
        Display_PutChar(((TmpF8/1)-(TmpF8/10)*10)+48);
        Display_PutString("F");
        Display_PutCRLF(0);
        
        CyDelay(2000);                                      //software pause for 2 seconds 
    }
}

/* [] END OF FILE */

I realize very few people would have experience with the setup I am using but so far its just the same as asny other 8-32bit micro using C, with the exception of the IDE allowing for schematic customization inside the chip it self, and being able to creat a PDF with all the info about my project, which if I knew a way to link it here in the forums, I'd link my project PDF to give further insight into how its set up.

[markaren1]

In terms of reading -ve values of temp, if after concatenating the two U8s into a U16...

Code: Select all

if(U16_TEMP & 0x8000)                                   // test sign bit
  S16_TEMP = -(S16)(U16_TEMP & 0x7FFF);      // make neg from bottom 15 bits
else
  S16_TEMP = (S16)(U16_TEMP);                      // keep as positive

may be of help.

You then (should/may) have a signed 16 bit temperature

HTH, mark

[Programability]

Thanks mark that will help with getting correct temperature readings.

As for my issue with calculated Checksum not matching up with transmitted checksum, I forgot to set the variables as signed integers.