Hi Guys

I'm trying to find an image like this one:

http://arduino.cc/en/uploads/Tutorial/Arduino_bb.png

but for the mega. Is there a library or something I cant find with this kind of stuff in it?

Thanks,

Mark.

Thank you so much!

I have actually spotted why my code didnt work (typical after 3 days staring at it!) but the solutions offered are so much simpler. It's the complexity of mine that had tripped me up.

Thanks again.

Mark.

Guys

Been lurking a while, but new to Arduino in general.

I'm developing a Ham Radion WSPR beacon using Arduino and I have everything working just fine, except....

I need to have a Calibration Factor to get my Arduino interfaced DDS exactly on frequency and I am trying to store and read back that value from EEPROM. It works fine for +ve numbers but not -ve. I've seen the tutorials on EEPROM writing but nothing I have seen has helped with -ve numbers.

I have tried including a bit test for the value read back, but this doesn't work either:

if (CalFactor >> 31 ==1) { CalFactor = CalFactor - (pow(2,32)-1); }

Can any kind soul here help with this connundrum of mine?

Here's the bit of code I can't get to function with -ve numbers, the value read back for a write of -2 is 288,741,374:

Code:

#include <EEPROM.h>
#include <math.h>

long CalFactor;
byte temp;
int j;
int i;

void setup()
{

   Serial.begin(9600);        // connect to the serial port

   CalFactor = -2;

   //Writes CalFactor to address 50 + 3 bytes of EEprom
   for (j=0; j<4; j++)  
   { // Step through 4 bytes to make 32 bit word
      for (i=0; i<8; i++)
      { // Step through 8 bit to make 1 byte
        bitWrite(temp,i,(bitRead(CalFactor,j*i+i))); // Assemble bits to make 1 byte
      }
      EEPROM.write(50+j,temp); // Write byte to EEprom
   }
  
   Serial.println("Written to EERPROM ");
   Serial.println(CalFactor);
   Serial.println(CalFactor,BIN);

   CalFactor = 0; // set all bits to zero
  
   // Read back from EEPROM
   for(j=0; j<4; j++)
   {  // Step through 4 bytes to make 32 bit word
      temp = EEPROM.read(50+j); // Get bytes 50 through 53
      for (i=0; i<8; i++)
      { // Set through 8 bit to make 1 byte
         bitWrite(CalFactor,i*j+i,(bitRead(temp,i))); // Assemble bits to make 32 bit word
      }
   }
  
   if (CalFactor >> 31 == 1)
   {
      Serial.println("1st Bit is 1");
//      CalFactor = CalFactor - (pow(2,32)-1);
   }
  
   Serial.println("Read from EERPROM");
   Serial.println(CalFactor);
   Serial.println(CalFactor,BIN);
}

void loop()
{  
}

Moderator edit: [code] [/code] tags added.