Just started using these chips(was using the 27/28c 128 for 3 years. My first burn was good!!! And verified to device. My question is when checking to see if chip is blank(or erased) it always says chip is not erased. And there is data in there upon checking. Is thisnormal since I am use to the 28c128 chips that always confirmed erased???? Or is it the shear nature of the chip to program over what was there??? BTW I am filling buffer with ff, and start device with 04000.This is for the 165 ecm. t.i.a.

 

Theres probably something residing on the first portion of the chip that you never program to.

 

The ATMEL 29C256 chips can be re-programmed without erasing first. To program them to all 0xFF like a typical erased device then you need to create a file of all 0xFFs and program it with that.

Basically, when you reprogram the chip, it does an erase internal to the chip before it writes from the internal SRAM buffer.

 

So I will never see the chip read blank?? thanks for the replies.

 

NO. Just program as if it was already blank.

Are you chaning the offsets for a 128/16k file?

File Size Chip Buffer Start -> End Chip Start -> End
4k (4096) AT29C256 000000 -> 000FFF 007000 -> 007FFF
16k (16384) AT29C256 000000 -> 003FFF 004000 -> 007FFF
32k (32768) AT29C256 000000 -> 007FFF 000000 -> 007FFF

Moates.net Setting Offsets

 

I am doing I think as instructed and using what you have listed under 16k.FWIW I am using 165 ecm 6e. New to the 29c256 chip burning, but have burned many of the "128s".

 

In case i missed it what eprom writer and software are you using?

You know what your doing though.

The AT29C256 chip is great in my book.

 

Intronics p.p. Thanks I hope I'm not just simply putting the same chip back in(never reprogrammed) again and again.!!!