power outage recovery using DS1307 Real Time Clock

OK, Some great help so far I have gotten this much running

/*
* Q(1-2) - (Q1) Memory Load  (Q2) RTC - Memory Read  
 
 */
#include "Wire.h"
#define DS1307_I2C_ADDRESS 0x68  // This is the I2C address
// Global Variables
int command = 0;       // This is the command char, in ascii form, sent from the serial port     
byte zero;
int  state   = 50;     // State machine variable
int  counter = 4;      // Master counter variable
int magnum1 = 99;      // dummy var
int magnum2 = 99;      //  dummy var

void setup() {
  Wire.begin();           // join i2c bus
  Serial.begin(57600); 
  zero=0x00;             // not sure what this is for
}

void loop() {
  if (Serial.available()) {      // Look for char in serial que and process if found
    command = Serial.read();

    if (command == 81 || command == 113) {      //If command = "Qq" RTC1307 Memory Functions
      delay(100);     
      if (Serial.available()) {
        command = Serial.read(); 
        if (command == 49) {                //If command = "1"  load data to RAM
          Wire.beginTransmission(DS1307_I2C_ADDRESS);   // 255 will be the init value and 0 will be considered 
          Wire.write(32);                   // Set the register pointer to before data location
          Wire.write(magnum1);              // Write magic number before storing data
          Wire.write(state);                // Store State variable
          Wire.write(counter >> 8);         // writes the high byte of counter
          Wire.write(counter & 0xFF);       // writes the low byte of counter
          Wire.write(magnum2);              // Write magic number after storing data
          Wire.endTransmission();

          Serial.println("Data Stored");
        }
        else if (command == 50) {      //If command = "2" Read data from RAM
          Serial.println("Begin Read");
          Wire.beginTransmission(DS1307_I2C_ADDRESS);
          Wire.write(zero);   // not sure what this is for 
          Wire.endTransmission();

          Wire.beginTransmission(DS1307_I2C_ADDRESS);
          Wire.write(0x20);         // not sure what this is doing
          Wire.endTransmission();
          Wire.requestFrom(DS1307_I2C_ADDRESS, 32);  // Set pointer to the first byte of data

          magnum1 = (Wire.read());  //magic number written before data write
          state = (Wire.read());    // Read state data
          counter = (Wire.read() << 8) + Wire.read(); // Read first byte shift left read second byte
          magnum2 = (Wire.read());  // Read Magic number written after data write
          Serial.print(" Magic Number = ");
          Serial.println(magnum1);
          Serial.print(" State = ");
          Serial.println(state);
          Serial.print(" Counter = ");
          Serial.println(counter);
          Serial.print(" Magic Number = ");
          Serial.println(magnum2);
          Serial.println(" RTC1307 Dump end");
        } 
      }  
    }
  }
  command = 0;                 // reset command 
  delay(100);
}
//********************************

now to figure out how to generate a random magic number

Is it OK if the random number has no magic properties?

Indeed

The random() function will return a pseudo-random number. For most purposes, that is good enough. The whole topic of true random numbers has been beaten to death here, so I won't go into all that you have to do to get true random numbers. Or, how to properly seed the random number generator.

The example code uses noise from an unused analog pin seed the random() function. I think that will be good enough. My application does not require TRUE random numbers. The repeating pattern would really be good enough.

Now enter maximum weirdness .
I took the older code and turned it into a couple of functions. I swear it worked last night very late. At work today this code froze at the uploading point and made my serial programming port unreachable. I determined that the ReadRTCRAM() function is to blame. Does this make any sense to anybody

/*
* Q(1-2) - (Q1) Memory Load  (Q2) RTC - Memory Read  
 
 */
#include "Wire.h"
#define DS1307_I2C_ADDRESS 0x68  // This is the I2C address


// Global Variables
long randNumber;
int command = 0;       // This is the command char, in ascii form, sent from the serial port     
byte zero;
int magnum1 = 90;      // dummy var
int magnum2 = 9;      //  dummy var

int  state   = 96;     // State machine variable
int  counter = 255;      // Master counter variable

void setup() {
   randomSeed(4);
  Wire.begin();           // join i2c bus
  Serial.begin(57600); 
  zero=0x00;             // not sure what this is for
}

void loop() {
  if (Serial.available()) {      // Look for char in serial que and process if found
    command = Serial.read();

    if (command == 81 || command == 113) {      //If command = "Qq" RTC1307 Memory Functions
      delay(100);     
      if (Serial.available()) {
        command = Serial.read(); 
        if (command == 49) {                //If command = "1"  load data to RAM
         WriteRTCRAM();
        }
        else if (command == 50) {      //If command = "2" Read data from RAM
          ReadRTCRAM();
        } 
      }  
    }
  }
  command = 0;                 // reset command 
  delay(100);
}
//********************************
void WriteRTCRAM(){
    randNumber = random(250);
  Serial.println(randNumber);  

 Wire.beginTransmission(DS1307_I2C_ADDRESS);   // 255 will be the init value and 0 will be considered 
          Wire.write(32);                   // Set the register pointer to before data location
          Wire.write(randNumber);              // Write magic number before storing data
          Wire.write(state);                // Store State variable
          Wire.write(counter >> 8);         // writes the high byte of counter
          Wire.write(counter & 0xFF);       // writes the low byte of counter
          Wire.write(randNumber);              // Write magic number after storing data
          Wire.endTransmission();

          Serial.println("Data Stored");
}
//********************************
void ReadRTCRAM(){
Serial.println("Begin Read");
          Wire.beginTransmission(DS1307_I2C_ADDRESS);
          Wire.write(zero);   // not sure what this is for 
          Wire.endTransmission();

          Wire.beginTransmission(DS1307_I2C_ADDRESS);
          Wire.write(0x20);         // not sure what this is doing
          Wire.endTransmission();
          Wire.requestFrom(DS1307_I2C_ADDRESS, 32);  // Set pointer to the first byte of data

          magnum1 = (Wire.read());  //magic number written before data write
          state = (Wire.read());    // Read state data
          counter = (Wire.read() << 8) + Wire.read(); // Read first byte shift left read second byte
          magnum2 = (Wire.read());  // Read Magic number written after data write
          Serial.print(" Magic Number = ");
          Serial.println(magnum1);
          Serial.print(" State = ");
          Serial.println(state);
          Serial.print(" Counter = ");
          Serial.println(counter);
          Serial.print(" Magic Number = ");
          Serial.println(magnum2);
          Serial.println(" RTC1307 Dump end");
          if (magnum1 = magnum2){
          Serial.print (" Write Error!!!");
          }
}

this is just too strange

    if (command == 81 || command == 113) {      //If command = "Qq" RTC1307 Memory Functions

Why not make it easy to read this code?

    if (command == 'Q' || command == 'q') {      // No comment needed; its obvious what to type
          magnum1 = (Wire.read());  //magic number written before data write
          state = (Wire.read());    // Read state data
          counter = (Wire.read() << 8) + Wire.read(); // Read first byte shift left read second byte
          magnum2 = (Wire.read());  // Read Magic number written after data write

(What's) (with) (all) (the) (parentheses) (?)

          if (magnum1 = magnum2){

Yeah, right. An assignment in the middle of an if statement...

          Wire.write(zero);   // not sure what this is for 
          Wire.write(0x20);         // not sure what this is doing

Don't you think you should figure these out?

Insert Quote

    if (command == 81 || command == 113) {      //If command = "Qq" RTC1307 Memory Functions

Why not make it easy to read this code?

Ok np but this is just temp code to get it running

          magnum1 = (Wire.read());  //magic number written before data write
          state = (Wire.read());    // Read state data
          counter = (Wire.read() << 8) + Wire.read(); // Read first byte shift left read second byte
          magnum2 = (Wire.read());  // Read Magic number written after data write

(What's) (with) (all) (the) (parentheses) (?)

Ok fixed

          if (magnum1 = magnum2){

Yeah, right. An assignment in the middle of an if statement...

Ah this is supposed to be

[code]
          if (magnum1 != magnum2){

[/code]

          Wire.write(zero);   // not sure what this is for 
          Wire.write(0x20);         // not sure what this is doing

Don't you think you should figure these out?

Well being new to the TWI I dont fully understand but I did find
Issue 527 : Stream-based Wire library doesn't accept zero
and the fix which I used.

and still after all of this I still cannot get this to upload unless I REM out the If statement.

and still after all of this I still cannot get this to compile unless I REM out the If statement.

Time to post new code, and the error messages.

/*
* Q(1-2) - (Q1) Memory Load  (Q2) RTC - Memory Read  
 
 */
#include "Wire.h"
#define DS1307_I2C_ADDRESS 0x68  // This is the I2C address


// Global Variables
long randNumber;
int command = 0;       // This is the command char, in ascii form, sent from the serial port     
byte zero;
int  state   = 96;     // State machine variable
int  counter = 255;      // Master counter variable
int magnum1 = 90;      // dummy var
int magnum2 = 9;      //  dummy var

void setup() {
   randomSeed(analogRead(0));
  Wire.begin();           // join i2c bus
  Serial.begin(57600); 
  zero=0x00;             // not sure what this is for
}

void loop() {
  if (Serial.available()) {      // Look for char in serial que and process if found
    command = Serial.read();

    if (command == 'Q' || command == 'q') {   
      delay(100);     
      if (Serial.available()) {
        command = Serial.read(); 
        if (command == 49) {                //If command = "1"  load data to RAM
         WriteRTCRAM();
        }
        else if (command == 50) {      //If command = "2" Read data from RAM
          ReadRTCRAM();
        } 
      }  
    }
  }
  command = 0;                 // reset command 
  delay(100);
}
//********************************
void WriteRTCRAM(){
    randNumber = random(250);
  Serial.println(randNumber);  

 Wire.beginTransmission(DS1307_I2C_ADDRESS);   // 255 will be the init value and 0 will be considered 
          Wire.write(32);                   // Set the register pointer to before data location
          Wire.write(randNumber);              // Write magic number before storing data
          Wire.write(state);                // Store State variable
          Wire.write(counter >> 8);         // writes the high byte of counter
          Wire.write(counter & 0xFF);       // writes the low byte of counter
          Wire.write(randNumber);              // Write magic number after storing data
          Wire.endTransmission();

          Serial.println("Data Stored");
}

void ReadRTCRAM(){
Serial.println("Begin Read");
          Wire.beginTransmission(DS1307_I2C_ADDRESS);
          Wire.write(zero);   // not sure what this is for 
          Wire.endTransmission();

          Wire.beginTransmission(DS1307_I2C_ADDRESS);
          Wire.write(0x20);         // not sure what this is doing
          Wire.endTransmission();
          Wire.requestFrom(DS1307_I2C_ADDRESS, 32);  // Set pointer to the first byte of data

          magnum1 = Wire.read();  //magic number written before data write
          state = Wire.read();    // Read state data
          counter = Wire.read() << 8 + Wire.read(); // Read first byte shift left read second byte
          magnum2 = Wire.read();  // Read Magic number written after data write
          Serial.print(" Magic Number = ");
          Serial.println(magnum1);
          Serial.print(" State = ");
          Serial.println(state);
          Serial.print(" Counter = ");
          Serial.println(counter);
          Serial.print(" Magic Number = ");
          Serial.println(magnum2);
          Serial.println(" RTC1307 Dump end");
          if (magnum1 != magnum2){
          Serial.print (" Write Error!!!");
          }
}

This compiles but will not upload

/*
* Q(1-2) - (Q1) Memory Load  (Q2) RTC - Memory Read  
 
 */
#include "Wire.h"
#define DS1307_I2C_ADDRESS 0x68  // This is the I2C address


// Global Variables
long randNumber;
int command = 0;       // This is the command char, in ascii form, sent from the serial port     
byte zero;
int  state   = 96;     // State machine variable
int  counter = 255;      // Master counter variable
int magnum1 = 90;      // dummy var
int magnum2 = 9;      //  dummy var

void setup() {
   randomSeed(analogRead(0));
  Wire.begin();           // join i2c bus
  Serial.begin(57600); 
  zero=0x00;             // not sure what this is for
}

void loop() {
  if (Serial.available()) {      // Look for char in serial que and process if found
    command = Serial.read();

    if (command == 'Q' || command == 'q') {   
      delay(100);     
      if (Serial.available()) {
        command = Serial.read(); 
        if (command == 49) {                //If command = "1"  load data to RAM
         WriteRTCRAM();
        }
        else if (command == 50) {      //If command = "2" Read data from RAM
          ReadRTCRAM();
        } 
      }  
    }
  }
  command = 0;                 // reset command 
  delay(100);
}
//********************************
void WriteRTCRAM(){
    randNumber = random(250);
  Serial.println(randNumber);  

 Wire.beginTransmission(DS1307_I2C_ADDRESS);   // 255 will be the init value and 0 will be considered 
          Wire.write(32);                   // Set the register pointer to before data location
          Wire.write(randNumber);              // Write magic number before storing data
          Wire.write(state);                // Store State variable
          Wire.write(counter >> 8);         // writes the high byte of counter
          Wire.write(counter & 0xFF);       // writes the low byte of counter
          Wire.write(randNumber);              // Write magic number after storing data
          Wire.endTransmission();

          Serial.println("Data Stored");
}

void ReadRTCRAM(){
Serial.println("Begin Read");
          Wire.beginTransmission(DS1307_I2C_ADDRESS);
          Wire.write(zero);   // not sure what this is for 
          Wire.endTransmission();

          Wire.beginTransmission(DS1307_I2C_ADDRESS);
          Wire.write(0x20);         // not sure what this is doing
          Wire.endTransmission();
          Wire.requestFrom(DS1307_I2C_ADDRESS, 32);  // Set pointer to the first byte of data

          magnum1 = Wire.read();  //magic number written before data write
          state = Wire.read();    // Read state data
          counter = Wire.read() << 8 + Wire.read(); // Read first byte shift left read second byte
          magnum2 = Wire.read();  // Read Magic number written after data write
          Serial.print(" Magic Number = ");
          Serial.println(magnum1);
          Serial.print(" State = ");
          Serial.println(state);
          Serial.print(" Counter = ");
          Serial.println(counter);
          Serial.print(" Magic Number = ");
          Serial.println(magnum2);
          Serial.println(" RTC1307 Dump end");
         // if (magnum1 != magnum2){
        //  Serial.print (" Write Error!!!");
         // }
}

This compiles and uploads

No error code green progress bar fills up to the last 3 white spaces and holds, to the left it says uploading.
Eventually I get a time out message. Waiting now so I can quote it.

avrdude: stk500v2_ReceiveMessage(): timeout
avrdude: stk500v2_ReceiveMessage(): timeout
avrdude: stk500v2_ReceiveMessage(): timeout
avrdude: stk500v2_ReceiveMessage(): timeout
avrdude: stk500v2_ReceiveMessage(): timeout
avrdude: stk500v2_ReceiveMessage(): timeout
avrdude: stk500v2_ReceiveMessage(): timeout
avrdude: stk500v2_getsync(): timeout communicating with programmer
avrdude: stk500v2_ReceiveMessage(): timeout
avrdude: stk500v2_ReceiveMessage(): timeout
avrdude: stk500v2_ReceiveMessage(): timeout
avrdude: stk500v2_ReceiveMessage(): timeout
avrdude: stk500v2_ReceiveMessage(): timeout
avrdude: stk500v2_ReceiveMessage(): timeout
avrdude: stk500v2_ReceiveMessage(): timeout
avrdude: stk500v2_getsync(): timeout communicating with programmer
avrdude: stk500v2_ReceiveMessage(): timeout
avrdude: stk500v2_ReceiveMessage(): timeout
avrdude: stk500v2_ReceiveMessage(): timeout
avrdude: stk500v2_ReceiveMessage(): timeout
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avrdude: stk500v2_ReceiveMessage(): timeout
avrdude: stk500v2_ReceiveMessage(): timeout
avrdude: stk500v2_getsync(): timeout communicating with programmer
avrdude: stk500v2_ReceiveMessage(): timeout
avrdude: stk500v2_ReceiveMessage(): timeout
avrdude: stk500v2_ReceiveMessage(): timeout
avrdude: stk500v2_ReceiveMessage(): timeout
avrdude: stk500v2_ReceiveMessage(): timeout
avrdude: stk500v2_ReceiveMessage(): timeout
avrdude: stk500v2_ReceiveMessage(): timeout
avrdude: stk500v2_getsync(): timeout communicating with programmer
avrdude: stk500v2_ReceiveMessage(): timeout
avrdude: stk500v2_ReceiveMessage(): timeout
avrdude: stk500v2_ReceiveMessage(): timeout
avrdude: stk500v2_ReceiveMessage(): timeout
avrdude: stk500v2_ReceiveMessage(): timeout
avrdude: stk500v2_ReceiveMessage(): timeout
avrdude: stk500v2_ReceiveMessage(): timeout
avrdude: stk500v2_getsync(): timeout communicating with programmer
avrdude: stk500v2_ReceiveMessage(): timeout
avrdude: stk500v2_ReceiveMessage(): timeout
avrdude: stk500v2_ReceiveMessage(): timeout
avrdude: stk500v2_ReceiveMessage(): timeout
avrdude: stk500v2_ReceiveMessage(): timeout
avrdude: stk500v2_ReceiveMessage(): timeout
avrdude: stk500v2_ReceiveMessage(): timeout
avrdude: stk500v2_getsync(): timeout communicating with programmer
avrdude: stk500v2_command(): failed miserably to execute command 0x13
avrdude: stk500v2_paged_write: write command failed
avrdude: stk500v2_ReceiveMessage(): timeout
avrdude: stk500v2_ReceiveMessage(): timeout
avrdude: stk500v2_ReceiveMessage(): timeout
avrdude: stk500v2_ReceiveMessage(): timeout
avrdude: stk500v2_ReceiveMessage(): timeout
avrdude: stk500v2_ReceiveMessage(): timeout
avrdude: stk500v2_ReceiveMessage(): timeout
avrdude: stk500v2_getsync(): timeout communicating with programmer
avrdude: stk500v2_ReceiveMessage(): timeout
avrdude: stk500v2_ReceiveMessage(): timeout
avrdude: stk500v2_ReceiveMessage(): timeout
avrdude: stk500v2_ReceiveMessage(): timeout
avrdude: stk500v2_ReceiveMessage(): timeout
avrdude: stk500v2_ReceiveMessage(): timeout
avrdude: stk500v2_ReceiveMessage(): timeout
avrdude: stk500v2_getsync(): timeout communicating with programmer
avrdude: stk500v2_ReceiveMessage(): timeout
avrdude: stk500v2_ReceiveMessage(): timeout
avrdude: stk500v2_ReceiveMessage(): timeout
avrdude: stk500v2_ReceiveMessage(): timeout
avrdude: stk500v2_ReceiveMessage(): timeout
avrdude: stk500v2_ReceiveMessage(): timeout
avrdude: stk500v2_ReceiveMessage(): timeout
avrdude: stk500v2_getsync(): timeout communicating with programmer
avrdude: stk500v2_ReceiveMessage(): timeout
avrdude: stk500v2_ReceiveMessage(): timeout
avrdude: stk500v2_ReceiveMessage(): timeout
avrdude: stk500v2_ReceiveMessage(): timeout
avrdude: stk500v2_ReceiveMessage(): timeout
avrdude: stk500v2_ReceiveMessage(): timeout
avrdude: stk500v2_ReceiveMessage(): timeout
avrdude: stk500v2_getsync(): timeout communicating with programmer
avrdude: stk500v2_ReceiveMessage(): timeout
avrdude: stk500v2_ReceiveMessage(): timeout
avrdude: stk500v2_ReceiveMessage(): timeout
avrdude: stk500v2_ReceiveMessage(): timeout
avrdude: stk500v2_ReceiveMessage(): timeout

Does commenting out just the Serial.print() statement make a difference? Does uncommenting that one, and commenting another make a difference?

Strangely yes commenting out the serial print statement did work.
????
Any Idea as to why this should act so?

Hello???

"crickets"

As it turns out !!! is the culprit.

Actually all arduino mega1280 and mega2560 boards both past and present suffer from the !!! bootloader monitor 'bug'. Doesn't matter what version board or version of IDE, the only fix is to upgrade the bootloader to one that has fixes that and other shortcomings of that bootloader.

Lefty

PaulS, you could not have just mentioned that???

// Serial.print (" Write Error!!!");

PaulS, you could not have just mentioned that???

I guess I could have,,, if I'''d read the whole statement,,, and seen that the statement contained data that was likely to cause problems...

The initial post said that commenting out three statements was required,,, to make the code upload. I was interested in finding out which of the three was the culprit...

As you can see from my reply, three punctuation marks in a row contribute nothing to the information. I don't understand why people feel it necessary to send more data than is necessary.

I don't understand why people feel it necessary to send more data than is necessary.

What is not necessary?