24LC256 wrong address at reading

[Fanias]

Hi Steve and thank you for your interest,
I did what you suggested and it works, however it's still not working when "addr" is in a For-next loop.
I get the same results, maybe I'm missing something in front of my eyes.
What i mean is that if i use the code in my first message (for addr = 0 to 5, where addr var word) I jump eeprom positions.
It drives me crazy, so I'll not spend more time on this, I have modified my code and will go that way with some more lines of code.

However, if anyone ever finds why this is happening, I would like to know
Thank you all for your answers and interest.

Fanis

Fanis,
Did you solve the problem?

I2CRead memSDA,memSCL,$A1,3,[text]

FYI, the "3" here is a constant, and is going to cause problems, since the 24LC256 needs a WORD addr.

try:

addr VAR WORD:addr=3
I2CRead memSDA,memSCL,$A1,addr,[text]

[SteveB]

addr var WORD

For addr = 0 TO 5                                        '  
I2CRead memSDA,memSCL,$A1,addr,[STR TEXT\6]     '$A0 does the same as $A1  
pause 10 
Next addr

Lets look at what this is doing. First, let's start with what's in the EEPROM. Starting at Address $00 (I put _ as placeholders for the value $FF):

            0123456789ABCDEF
$0000-000F: HELLO!__KM17WS__

The 1st time through the loop, addr = 0, the PIC sets the register address in the 24LC256 to $0000, then reads 6 bytes sequentially, and puts them into TEXT = "HELLO!"
The 2nd time through the loop, addr = 1, the PIC sets the register address in the 24LC256 to $0001, then reads 6 bytes sequentially, and puts them into TEXT = "ELLO!_"
The 3rd time through the loop, addr = 2, the PIC sets the register address in the 24LC256 to $0002, then reads 6 bytes sequentially, and puts them into TEXT = "LLO!__"
...
The 6th time through the loop, addr = 5, the PIC sets the register address in the 24LC256 to $0005, then reads 6 bytes sequentially, and puts them into TEXT = "!__KM1"

At least that's the way it should be working. I'm not sure why you got "M__KM1".

However, now hopefully you see why, when you changed the FOR...NEXT loop to count from 3 to 8, it gave you "KM17WS"

It's because on the last loop addr = 8, the register address set in the 24LC256 is $0008, then it reads 6 bytes sequentually, and you end up with TEXT = "KM17WS"

That help?

[Fanias]

addr var WORD

For addr = 0 TO 5                                        '  
I2CRead memSDA,memSCL,$A1,addr,[STR TEXT\6]     '$A0 does the same as $A1  
pause 10 
Next addr

Lets look at what this is doing. First, let's start with what's in the EEPROM. Starting at Address $00 (I put _ as placeholders for the value $FF):

            0123456789ABCDEF
$0000-000F: HELLO!__KM17WS__

The 1st time through the loop, addr = 0, the PIC sets the register address in the 24LC256 to $0000, then reads 6 bytes sequentially, and puts them into TEXT = "HELLO!"
The 2nd time through the loop, addr = 1, the PIC sets the register address in the 24LC256 to $0001, then reads 6 bytes sequentially, and puts them into TEXT = "ELLO!_"
The 3rd time through the loop, addr = 2, the PIC sets the register address in the 24LC256 to $0002, then reads 6 bytes sequentially, and puts them into TEXT = "LLO!__"
...
The 6th time through the loop, addr = 5, the PIC sets the register address in the 24LC256 to $0005, then reads 6 bytes sequentially, and puts them into TEXT = "!__KM1"

At least that's the way it should be working. I'm not sure why you got "M__KM1".

However, now hopefully you see why, when you changed the FOR...NEXT loop to count from 3 to 8, it gave you "KM17WS"

It's because on the last loop addr = 8, the register address set in the 24LC256 is $0008, then it reads 6 bytes sequentually, and you end up with TEXT = "KM17WS"

That help?

You make me feel stupid , but I forgive you it's always good to learn something new.
My mistake is clear about the use of the STR modifier, however can you help me with the I2cwrite command ?

Addr=0
I2cwrite memsda,memscl, $a0, addr, [str text\5]

The above is not working or maybe STR is only used at "read" commands ?
This works for me instead :

I2cwrite, memsda, memscl, $a0, addr, [text[0], text[1],......, text[4]]

A big thanks
Fanis

[SteveB]

You make me feel stupid , but I forgive you

Sorry, didn't mean to come across that way, just wanted to make sure my explanation was clear.

Addr=0
I2cwrite memsda,memscl, $a0, addr, [str text\5]

The above is not working or maybe STR is only used at "read" commands ?
This works for me instead :

I2cwrite, memsda, memscl, $a0, addr, [text[0], text[1],......, text[4]]

Not sure why [STR TEXT\5] didn't work, it should have.

[pedja089]

There must be pause 5ms after writing before next operation.