I2C Smart Card memory

Usually I2C EEPROM's have defined address and this is found on the Data sheets.

But I cannot find such data sheet regarding the Smart Card type I2C EEPROMS. Also on the cards there is no indication of the manufacturer.

Any ideas?

Ioannis

Try to scan all addresses.
Something like this

Code:

---

FOR i = 0 TO 255
    Adr VAR BYTE/WORD depending on memory size expected
    ADR=10
    I2CWRITE datapin,clock,i,Adr,[123]
    PAUSE 10
    TestByte=0
    I2CREAD datapin,clock,i,Adr,[TestByte]
    IF TestByte=123 THEN
        Write 0,i
        END
    ENDIF
NEXT i

---

And after few seconds read eeprom of PIC, Or you can use serout to show address on PC, etc...
I guess it should be $A0.
Can you post picture of smart card, so someone can recognize it and find internal schematic?

Thank for the reply.

Sure I will post a picture, but it is a classic blank card.

May be the chip is recognizable.

Attachment 8135

Ioannis

It looks like there is more than just eeprom in card.
http://www.cdrinfo.com/Sections/News...x?NewsId=23488

OK, I tried $A0 and sure seems that this is the correct value.

But, there is another issue.

Writing say 1024 bytes and doing write/verify is succesful, if power is cycled, the read data is wrong and the same value. Either 16,255 or 0.

Ioannis

Many moons ago I bought some of the blank memory cards, and I THINK I got them from.........Crownhill !!!

Perhaps you could drop Lester a line and see if they did supply these cards at one time.

I never did get round to using them, but I did write on one card the pinout, but nothing about the address and I cannot see in my pdfs any data sheet for these.

C1 5v , C3 SCL, C5 GROUND, C7 SDA. C2,C4,C6,C8 NO CONNECTS.

From what I remember, the memory inside was 24lc16, and there are 8 banks of 256 bytes, so if your card is the same you have to write in blocks of upto 256 per block then change to next bank.
The control I use for 24LC16
RBANK0 CON %10100000 'CONTROL CODE OF MEM IC FIRST 256BYTES
RBANK1 CON %10100010
RBANK2 CON %10100100
RBANK3 CON %10100110
RBANK4 CON %10101000
RBANK5 CON %10101010
RBANK6 CON %10101100
RBANK7 CON %10101110

Also remember the need for pullups.

Thanks for the info.

The card that I post a photo seems to respond correctly as an 64K address EEPROM.

I write and read just fine. Only when I cycle its power, the date is lost.

It has to do I think with the page write but cannot find a way to control that.

Ioannis

For test, try to write single byte every time, and wait 5ms, between each write.
That would eliminate page write issue.

As long as the power is on, data appears to be written.

Including the one byte test. But if card is removed and re-inserted, data gets lost.

Ioannis

Then that doesn't have anything with page write.
Just guessing, maybe there are only some serial number permanently stored in eeprom, and other location are unimplemented?

It is very bizzare that it seems to write succesfully in every location for as long as the power is ON.

I'll some more tests and report back.

I have also available a couple of SLE4442 but have never tried that for writing.

Ioannis