Another attempt for I2C eeprom, this time - 25C256.

[mpgmike]

C1, if you have the spare cash, I would recommend a cheap logic analyzer. Saelig sells one for (I think I paid) around $80 US. I haven't used mine in several years, as I now have a Pico Scope that does much more, and better. I am in the northeast US. If you're willing to cover shipping, you can have my old Saelig. It will help you to verify communication protocols and baud rates for situations like this. If interested, PM me & we can take it from there. You might be able to find one on eBay, Amazon, or Craigslist (or whatever local online sellers site you have) for next to nothing, and with cheaper or even no shipping.

[CuriousOne]

So what's wrong with 160? it is chip address, A0, and isn't that fixed?

Regarding the logic analyzer. I have that saelae thing.
I can't get it work as I understand it should work - run continuously, monitor bytes, like scope does. it only has "run", it runs, fills up buffer in couple of seconds and stops - that's all. For that purposes, I bought a scope with built-in logic analyzer, which can run infinitely - Hantek DSO2D10 - but was able it to work only very low speeds, for protocol decoding.

[richard]

it a constant , pbp constants are 16 bits , i2c address are 8 bit
use your logic analyzer

[CuriousOne]

So what should I write instead of 160?

I've searched this forum, and people do use plain numbers in I2C eeprom write/read?

[richard]

Address var byte
Address = 160

[HenrikOlsson]

Yeah, you really should spend some time getting that logic analyzer working and understand what it does. It's NOT an oscilloscope and although newer versions of the software does allow it to continously stream and display that's not really its intended purpose.

Anyway, here's what I'd try (and I'd have the logic analyzer hooked up)

Chip_Address	VAR BYTE
Mem_Address	VAR WORD
sda		VAR portb.1
scl		VAR portb.0

Chip_Address = 160

' The chip address must be a BYTE, this is the 160 + whatever A0-A2 is set to.
' The memory address must be a WORD for the 24C256, this is the address of the byte to written (or read)
' The data to be written is, in this case, a BYTE but it does not have to be, you can write words or arrays - which are obviously just multiple bytes...

FOR Mem_Address = 0 to 12
  '        I/O  I/O       BYTE        WORD             BYTE
  I2CWrite sda, scl, Chip_Address, Mem_Address, [Mem_Address.LOWBYTE]
NEXT

And I'd like to thank Richard for the primers on PBP I2C the last couple of days, much appreciated!

[CuriousOne]

WOW! Finally it works!

x var word
y var byte
adr var byte
sda var portc.0
scl var portc.1
lcdout $fe, $01, " "
adr=160


for X=0 to 5 
I2CWrite sda, scl, adr, x, [x.lowbyte]
lcdout $fe, $14, dec x


pause 100
next
pause 500
lcdout $fe, $1, "Complete:" 
lcdout $fe, $c0, " "
pause 500


for x=0 to 5  
i2cread sda, scl, adr, x, [y]
lcdout $fe, $14, dec y
pause 100
next
stop

That's very good, this means now I can do a lot of LCD things!

Thanks everyone!

by the way, I tried to write 160 directly, instead of adr - also works.