Values in Hex in EEPROM

sharmait

Hi Peter,

I have been using·the program EETest.java to write values to EEPROM and then dump the·memory using·EEdump.java.·Everything is fine but whenever I try to write a·odd number·to the EEPROM (e.g SetEEPROM(4367) or SetEEPROM(5)), I see a rounded up value in HEX when I dump the memory. For example 4367 showed as 10AA (correct value should have been 10AB) and 5 showed as 4. It is always 1 less than the actual number. I had no problem with even numbers.

Can you please help me on this ?

Thanks,
Sharmait.

Peter Verkaik

please post your program.

regards peter

sharmait

Here are the two programs that I am using :

For "stamp.util.text.*" I am using the text format library·from parallax website http://www.parallax.com/javelin/applications.asp#AN012

EETest Program

=================================

import stamp.core.*;

public class EETest {

static void setEEProm(int n) {
EEPROM.write(0,(byte)(n&0xFE));
EEPROM.write(1,(byte)(n>>8));
}


static int getEEProm() {
int x;
x=EEPROM.read(1);
x=(x<<8)+EEPROM.read(0);
return x;
}


public static void main() {
setEEProm(4267); //This is where I set an ODD value//
System.out.println("Bytes available in EEPROM:");
System.out.println(EEPROM.size());
System.out.println("The value you wrote to EEPROM:");
System.out.println(getEEProm());
} // end main
} // end class

==============================

Memory dump program
=============================
import stamp.core.*;
import stamp.util.text.*;
/**
·* Print the javelin's eeprom
·*
·* @version 1.0, April 12, 2005
·* @author Peter Verkaik (peterverkaik@boselectro.nl)
·*/
public class memdump {
· /**
·· * Print free area of javelin eeprom to the message window.
·· */
· static void printEeprom() {
··· int x,y;
··· char c;
··· for (x=0000;x<EEPROM.size()/16;x++) {
····· Format.printf("%04x : ",(x*16));··············· /* Display the address··············· */
····· for (y=0;y<16;y++) {····························· /* write the contents in hex······· */
······· Format.printf("%02x ",0xFF & EEPROM.readAll((x*16)+y));
····· }
····· for (y=0;y<16;y++) {······················· /* Display the ASCII-characters······· */
······· c = (char) EEPROM.readAll((x*16)+y);
······· if ((c>=' ') && (c<=0x7E))
········· Format.printf("%c",c);
······· else
········· Format.printf(".");
····· }
····· Format.printf("\n");······················· /* New line······················· */
··· }
· }
· static void main() {
····printEeprom();
··· while (true);
· }
}

Thanks Very Much !
Sharmait.

Peter Verkaik

In your routine

static void setEEProm(int n) {
EEPROM.write(0,(byte)(n&0xFE));
EEPROM.write(1,(byte)(n>>8));
}

you do a bitwise AND with 0xFE (i.e clear bit0)

so when you read it back any odd number appears to be even.

You must AND with 0xFF, but you can also

just use EEPROM.write(0,(byte)n);

as only the lowest byte is written.

regards peter

sharmait

Thanks very much !!

Yes I see now where the error is...

Sharmait.

sharmait

Hi,

Just wanted to mention that the EETest.java program that I am using came with the Parallax Javelin Stamp CD (in examples). So as far as the·bitwise AND with FE(EEPROM.write(0,(byte)(n&0xFE)) is concerned, is it is bug or has been put there for some reason ? Just checking in case we want to update the EEtest.java program in the parallax CD.

Thanks...

Peter Verkaik

I think it was a typing error.

regards peter