quote:

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Originally posted by crtguy

I have a couple 27C1001 chips from NEC with model number D27C1001D-15. They are pulled from a working board that can self-test and reports correct CRC check. I have a copy of the ROM file and need to burn one for another, identical board.

I cannot read/write to it using the generic 27C1001, the D27C1001A, or the MBM27C1001 setting. All data comes back as junk when reading and outright fails when writing. Blank-check passes fine once erased.

I can read (roughly) the first half correctly using the 27C100 setting but the second half reads blank (but I know there's data there). Looks like it fails reading somewhere between address 0000F130 - 00010000

EDIT - This is all I could find for datasheets:

h**ps://datasheetarchive.com/pdf/download.php?id=077e9985963ad6b770590dbc31ec81a99ee814&type=M&term=UPD27C1001

h**p://pdf.icpdf.com/PdfOld/icpdf_datasheet_4/UPD27_datasheet_4249/723780/UPD27_datasheet.pdf

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quote:

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Originally posted by anniel

Do you get an ID?

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quote:

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Originally posted by crtguy

quote:

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Originally posted by anniel

Do you get an ID?

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I think I found my issue while trying to ID the chip. See below.

Using 27C1001 generic setting
Device ID: FFFF
Manufacturer: Not in library
Type: Unknown Device
Revision: -

Using D27C1001A setting
Device ID: FFFF
Manufacturer: Not in library
Type: Unknown Device
Revision: -

Using M27C1001 setting
Device ID: FFFF
Manufacturer: Not in library
Type: Unknown Device
Revision: -

Using MBM27C1001 setting I get a few different results?!?
First try:
Device ID: FF46
Manufacturer: Not in library
Type: Unknown Device
Revision: -
Second try:
Device ID: 1046
Manufacturer: NEC
Type: Unknown Device
Revision: -
Third try:
Device ID: 3F46
Manufacturer: Not in library
Type: Unknown Device
Revision: -

Getting varying results was a little concerning. I confirmed the same issue with another of the same ROM chips, it usually wasn't until the second or third ID check that it would report NEC.

I took some compressed air and cleaned out the GQ-4x4 ZIF socket. I also brushed both chip's legs with a light abrasive.

I can now read and ID the chips perfectly each time using the MBM27C1001 setting.

Thank you.

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Write failed, Address=0x000001, Buffer=0x01 Device=0x00

00 01 02 03 04 05 06 07 01 01 03 01 02 01 01 FF

00 01 FF FF FF FF FF FF FF FF FF FF FF FF FF FF

Name="D27C1001D-15",ID="1046",Class="HN27C101",VCC="5V",WVPP="12.5V",WVCC="6.5V",RVPP="5V",Category="EPROM",MFG="NEC",Message="TEST";

quote:

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Originally posted by crtguy

I may have jumped the gun. Using the MBM27C1001 setting; reading and blank-checking are no issue but I haven't been able to write to either of the two chips I've erased.

I always get an error within the first few seconds stating

Write failed, Address=0x000001, Buffer=0x01 Device=0x00

The bin file I'm trying to write has the following at offset 00000000

00 01 02 03 04 05 06 07 01 01 03 01 02 01 01 FF

And when I read back after the write error I get

00 01 FF FF FF FF FF FF FF FF FF FF FF FF FF FF

So I'm note sure why the device is erroring out, as it looks like 0x000001 was written correctly.

I took a closer look at the full datasheet I linked and it's for D27C1001AD-xx, not necessarily D27C1001D-15. The partial Japanese datasheet lists uPD27c1001D-15 and the voltage specs for reading & writing appear the same across the board. Using that info I created this custom device:

Name="D27C1001D-15",ID="1046",Class="HN27C101",VCC="5V",WVPP="12.5V",WVCC="6.5V",RVPP="5V",Category="EPROM",MFG="NEC",Message="TEST";

Using the new custom setting, I get the exact same results. Errors out writing at Address=0x000001, and the same data (as above) returns when reading after the error.

It's not the end of the world if I have to replace them with another 1Mb EPROM from a different manufacturer, but it would be nice to reuse these if possible.

Other items of note:
- Both chips had good data on them before they were erased (verified by PCB's self-test CRC check).
- I'm able to read an identical NEC chip I haven't erased using the custom device setting.
- I have/had seven of these NEC chips to start with, all physically identical, all pulled from identical hardware (same PCB model & production run), all had good data to start (some were duplicates, hence why I want to rewrite them).

Appreciate all the help!

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Name="D27C1001D-15",ID="1046",Class="HN27C101",VCC="5V",WVPP="12.7V",WVCC="6.5V",RVPP="5V",Category="EPROM",MFG="NEC",Message="TEST";