28 series EEPROM woes

Tried to program a bunch of old 28 series EEPROMs with my T56 without success.

1) Xicor X2864AP-45. The programmer seems fail detecting the /OE pin correctly using the Xicor X2864AP profile. Reading the chip seems to work fine. There's no erase option even though this is an EEPROM. Erasing the chips using another 2864 chip works partially, some bytes will not change though.

Suspecting this could be due to timing issues. There are several versions of X2864AP, the 45 ns one is the slowest.

2) Xicor X2864AD-45. Same as above. Assuming the only difference between the P and D versions is plastic vs ceramic packaging.

Also noticed that the erase option is missing from several (if not most) 28 series chips while (unsuccessfully) trying to work with these chips using other profiles.

Please go through the 28 series EEPROM profiles, prioritizing the above.

Also please add the Intel D2864A-25 EEPROM.

See attached screenshots.

Thanks in advance!

Xicor_X2864AP-45.jpg (366.83 KB)

Xicor_X2864AD-45.jpg (355.47 KB)

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Test发表于 2022-12-6 05:49 | 只看该作者

This datasheet might be of help for adding profiles for the different Xicor X2864AP versions, http://www.datasheet.hk/view_dow ... Cx2864ap_200790.pdf

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admin发表于 2022-12-6 14:08 | 只看该作者

回复 1# Test

Many manufacturers of 28s chips do not have a special erase command. You can write FF instead of erase．
Detecting of Pins is an auxiliary function. some pins maybe not detected.

-25 - 45 should not matter. T56 delays nearly 200ns for 28 series chips．

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Test发表于 2022-12-6 18:27 | 只看该作者

回复 Test

Many manufacturers of 28s chips do not have a special erase command. You can write FF ...
admin 发表于 2022-12-6 14:08

Thanks for your reply :)

Erasing by writing FF-filled buffer to the chip results in the same as erasing using some other 2864 chip profile with erase function present. Some bytes will not erase. See attached screenshot. Tried with several different X2864AP-45 chips. All of them gives the same result, so doubting it's due to faulty chips at least.

The X2864AP-45 is a 450ns chip (looks like I forgot a 0 in my first post). Is it possible to edit the programming parameters somehow? Would like to try with higher delays, unless you can can say for sure this isn't the problem, or got something else to try.

My T56 also appears to work perfectly otherwise. Programmed a bunch of 27 series EPROMs, PIC MCU:s and ATTiny MCU:s without problems since I got it a couple of weeks ago. It also passes the self test.

Xicor_X2864AP-45_2.jpg (324.45 KB)