Electronics > Repair
Need Help Programing an 93C46 EEPROM. I Can Read and Erase But Not Write.
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Chooch_Fiesta:

--- Quote from: DavidAlfa on January 27, 2024, 09:16:45 pm ---Try:
https://github.com/McMCCRU/SNANDer



--- End quote ---

Thank you I'll take a look into this tonight.
Chooch_Fiesta:

--- Quote from: Psi on January 27, 2024, 09:27:41 pm ---If you unsoldered this from a car alarm there is a possibility this IC is not 100% the same as what you think based on markings that say 93C46.

It could be a custom sku of the 93C46, or maybe it has a silicon fault and was sold cheap to specific customers along with documents that provide a work-around.
Perhaps there is a mark on the IC to indicate this but only the manufacturer can tell and to anyone else it looks like a date code.
i.e, It may appear to be a 93C46 but not actually match the datasheet exactly.

Maybe order a new official chip and try that,  assuming the car alarm just reads the chip and it sounds like you can read it that should still work fine.

--- End quote ---

It's not from the full alarm just the alarm buzzer. These are from cars built 20 years ago but we're still used till about 2013. There are a few cars that use the same unit but there is a difference in the firmware on the bios for how the alarm operates when the car is locked. One unit is incredibly expensive and the other is very cheap. All fail the same way due to the internal NiCad batteries failing and destroying the PCB as seen in the pictures I posted.

It was proven by a few people that they were able to read the 93C46 of the expensive unit and flash the cheaper unit getting the same operation. They don't explain their setup just that they used ponyprog.

Another person is also able to do it but he will not explain how he does it because he sells flashed units for half of the expensive unit price but still 10x what I paid for a used buzzer on eBay.

I'm just trying to grab the firmware I saved from my unit and reflash it.

The issue is I was able to backup the firmware but I can't write it back to the chip. Doesn't matter if I try to flash 1 but or try to flash the full recovery file I made.

I measured the ORG pin on the PCB of the good buzzer and it looks like it has continuity with VCC not ground like the damaged PCB. So now I think I was wrong and it is actually in X16 configuration.

I rewired the 93C46 for X16 with ORG tied to VCC with a 10K resistor.

I am still able to read in both programs but NeoProgrammer will not erase and still neither will write.

I hope I am being as clear as possible.
Chooch_Fiesta:
Maybe not super helpful but I was able to grab a 24C08AN EEPROM off a random scrap PCB I found and I was able to read, save, and write to it no issues.

I was able to modify the buffer and write, and I was able to write a backup of the memory back to the EEPROM.

I guess it must be an issue with 93C46 itself. The board was very heavily damaged as you can see in my first post.

Maybe I just have to wait till I get a new chip and see if it has the same write issue.

Otherwise I have no idea what I am doing wrong.
Chooch_Fiesta:
I was able to solve the programming issue now I just need to determine if the chip is written as X8 or X16.

In the original post I thought it was X8 because I measured the ORG pin connected to ground but I believe that the alarm circuit on the PCB was just too damaged and there was a short.

I measured (and looked) and the good PCB has the ORG pin in continuity with VCC.

Also based on the image that the person who said they were able to do it before using PonyProg, they have there buffer window showing 16x hyphenated  strings of bits.

Would I be correct that the EEPROM is actually X16 config and not X8? If I flash it in one config and test it shouldnt hurt to flash the other as well and try again if it doesn't operate properly.

Psi:
I wouldn't trust how it displays in the app to mean anything.
I've not played with ponyprog but you can probably set it up to display however you want.
I doubt it means anything about the chip data it read.

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