I2CWRITE problem

[Gusse]

My code is working well

I found a reason for problem and I must admit it is purely due to my own stupidity. I have two identical (home made) test boards and when I measured I2C voltage, I measured from wrong board. Board which had I2C test SW was not properly powered. Meaning that one of the PIC IO pin is supply for I2C and that pin was not set to "1". No power, no EEPROM. How stupid of me!

It might have something to do that this is my fourth day in flu and fever. Brains are not anymore working well...

BR,
-Gusse-

[Archangel]

My code is working well

I found a reason for problem and I must admit it is purely due to my own stupidity. I have two identical (home made) test boards and when I measured I2C voltage, I measured from wrong board. Board which had I2C test SW was not properly powered. Meaning that one of the PIC IO pin is supply for I2C and that pin was not set to "1". No power, no EEPROM. How stupid of me!

It might have something to do that this is my fourth day in flu and fever. Brains are not anymore working well...

BR,
-Gusse-

Don't be so hard on yourself, people (especially sick ones) make mistakes.

[Dave]

Art, I have used external eeproms on most all of my projects and have never had any problems with bad data. I just make sure I dont have any interrupts during the write cycle and always use 2.2k resistors for the pullups. I am currently using 2 x 24LC1025's for about a months worth of data storage on a solar telemetery project and haven't had a bad bit all summer or winter. So far its been -5 degrees a couple of nights here.. I would suggest maybe using 2.2k resistors for the pullups and the I2C_SLOW command. I also never use more than 6 milliseconds of delay after the write... Good Luck...

Dave Purola,
N8NTA

[MR2010]

hi art im newbe but if im right i noticed an error in your code .sorry if its not.

W0 var byte
epin var word   <<<<<  i think this is address ?

W0 = 0
FOR cntr = 0 TO 2000  	'should be( FOR epin= 0  TO 2000 )!	or (cntr)should be var  xxx
epin = epin + 5		'
I2CWRITE porte.1,porte.2,%10100000,epin,[W0,W0,W0,W0,W0],error	
pause 10						'
						'
NEXT cntr

hope this helps
see Gusse code moght it helps

[MR2010]

hi gusse guess SDA PORTD.1 is always input what will happens ? u did set SDA port input only read .u have to leave trisd alone and set portd = 0 , i can say trisd s gone to charge you lol

TRISD.0 = 0
TRISD.1 = 1 '<<<should be TRISD.1 = 0  or  only PORTD = %0000  
TRISD.3 = 0
TRISE.4 = 0

SCL     VAR PortD.0 
SDA     VAR PortD.1   
LED     VAR PortD.3


END

im newbe hope this helps
hope u get better gusse
regards

[Gusse]

hi gusse guess SDA PORTD.1 is always input what will happens ? u did set SDA port input only read .u have to leave trisd alone and set portd = 0 , i can say trisd s gone to charge you lol

im newbe hope this helps
hope u get better gusse
regards

To my understanding I2CWRITE and I2CREAD -functions take care of port settings. So basically, whatever user is pre-defining in SW, I2C-routine will over-write it.
- I2C clock is always coming from master (PIC) and it is output.
- I2C data is bi-directional, so port will change between input and output.

Please, somebody wiser correct if I'm totally wrong.

I2CAddressEEprom = 0 TO 1024

Value should be 1023. 0 + 1023 = 1024.

BR,
-Gusse-

PS. Getting better, little by little ...

[Art]

hi art im newbe but if im right i noticed an error in your code .sorry if its not.

W0 var byte
epin var word   <<<<<  i think this is address ?

W0 = 0
FOR cntr = 0 TO 2000  	'should be( FOR epin= 0  TO 2000 )!	or (cntr)should be var  xxx
epin = epin + 5		'
I2CWRITE porte.1,porte.2,%10100000,epin,[W0,W0,W0,W0,W0],error	
pause 10						'
						'
NEXT cntr

hope this helps
see Gusse code moght it helps

Yes epin is an address word but it is incremented by the line:
epin = epin + 5 in the code I provided.
This is correct because the I2CWRITE command has written five addresses sequentially.
The cntr var should be declared at the top, I forgot that.

Art, I have used external eeproms on most all of my projects and have never had any problems with bad data.

Hi Dave,
Solar electricity rules, and if you use it to run a fridge it slaps nature in the face
I'll try a paralel resistor value to equal 2.2K, and retry the DEFINE I2C_SLOW 1.
Normally I don't have problems with EEPROMS either.

One other thing.
I have introduced five new byte vars, and done a readback of the five
written bytes so the program can verify what was read from the EEPROM is
the same as what was written 10ms ago.
If the results don't match, it goes back to rewrite the original (correct) values.

When it gets to one of the addresses in question, it just hangs there
rewriting all the time, and never getting the data right.

[MR2010]

I JUST DESCOVERED THE BLOODY PROBLEM IS

I2CAddressEEprom    VAR WORD

WHEN U PUT VAR BYTE IT WORKS GREAT BUT WHEN U PUT VAR WORD IT DOESNT IT WRITES ONLY 4TH BYTE .IM CONFUSED THE PROBLEM IS IN THE ADRESS OR THE DATA X,

HOPE U CAN FIND IT GUYS
GOOD LUCK ..!

[Art]

Whether you use a word or byte address depends on the EEPROM device.
It's in the manual for I2CREAD.