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ZLM
2937 Posts |
 Posted - 02/10/2008 : 14:07:26
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The AT29C256 flash chip is no longer manufactured and it is hard to find it.
However, it can be replaced by SST27SF512 with set the programming offset to 8000 address.
In GQ-2X, GQ-3X True USB Willem programmer software, follow the following steps:
1. Run GQ programmer software
2. Select device type SST27SF512
3. set the 8000 value in File Offset box.This is chip start address when progrmming on chip.
4. load the data file (originally for AT29C256)
5. place the chip into ZIF socket.
6. Erase and do a blank check on chip.
7. Write the chip
The write process should complete and followed by a successful verification.
Now your chip is ready to use.
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| Reply #1
ZLM
2937 Posts |
Posted - 04/15/2008 : 10:26:56
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The AT29C256 and the SST27SF512 have different data size. They are different chip. This is why we set the offset to convert the original AT29C256 data file to SST27SF512 data. So that we can write the AT29C256 data into the 27SF512 chip.
If we read the data from the 27SF512 chip, we should get the 27SF512 data with the offset 8000, not the original AT29C256 data. In this case, you can save the data file, and next time, you do not need set the file offset 8000. Because the data file is the 27SF512 file already.
If you want to read out the original AT29C256 data, then you have to select the AT29C256 from the software, but place the SST27SF512 in the ZIF socket. This time the 8000 offset is filtered out.
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| Reply #2
Six_Shooter
11 Posts |
Posted - 05/02/2008 : 19:07:02
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quote:
Originally posted by ZLM
The AT29C256 and the SST27SF512 have different data size. They are different chip. This is why we set the offset to convert the original AT29C256 data file to SST27SF512 data. So that we can write the AT29C256 data into the 27SF512 chip.
If we read the data from the 27SF512 chip, we should get the 27SF512 data with the offset 8000, not the original AT29C256 data. In this case, you can save the data file, and next time, you do not need set the file offset 8000. Because the data file is the 27SF512 file already.
If you want to read out the original AT29C256 data, then you have to select the AT29C256 from the software, but place the SST27SF512 in the ZIF socket. This time the 8000 offset is filtered out.
I have no problem with the programming, that works fine.
I am having a problem with the reading though. I can read the 27SF512 as a 512 chip and get the data, at the end of the chip, starting with F000, since it's a 4K bin, and how the chip needs to be to work.
Anyway, I have not been able to use the original chip size to automatically offset the read and save as a 4K file. At this point I need to open the bin file with notepad and edit out the first part of the file manually.
I've tried installing the 2.08beta software and this has not changed.
Any ideas? |
Edited by - Six_Shooter on 05/02/2008 20:00:51 |
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| Reply #3
ZLM
2937 Posts |
Posted - 05/03/2008 : 00:17:33
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The SST27SF512 should have 64K bytes binary data. And the only end 32K byte is used. The begining 32 Kb is empty.
So, the saved file is in 64Kb and should work without set offset value on SST27SF512 chip. |
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| Reply #4
DJEsco
USA
6 Posts |
Posted - 02/08/2010 : 13:40:01
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As we are all now discovering SST27SF512 chips are also no longer being manufactured.
and as many I am seeking a 28 pin replacement.
I welcome any feedback or suggestions on this matter.
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(832)798-0000 |
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| Reply #5
ZLM
2937 Posts |
Posted - 02/09/2010 : 10:15:15
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| I think the MCUmall still can supply SST27SF512 DIP chips, even it stopped production. |
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| Reply #6
DJEsco
USA
6 Posts |
Posted - 02/15/2010 : 00:03:03
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 how many do you have left?
By the way I see you have the 84 Pin PLCC IC Socket. These come in handy when chipping OBD2 Hondas |
(832)798-0000 |
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SST27SF512 vs AT29C256
