If 27C128 is the prom type for a '165 maf, Is an "EEPROM" for a '165 maf ecm still considered a 27C128 ?

I'm looking to buy some EEPROMS, and wondering what to buy and who's the best vendor


Anybody have good success with a specific brand/company? thanks

 

Buy them used elctronic surplus, and an eraser would be nice. New they run about 5$ a piece for chips. I have been getting batches of 10 on ebay used and erased (27c128, 256, and 32) for 5$. I have had a problem with some of them not being erased, but 90% of them have been. erased

 

Ok used...

But is it still considered a 27C128 if its EEPROM instead of PROM?

 

No. You are confused. EPROMs are eraseable via UV Light. EEPROMs are Electonically Eraseable. 27C128 refers to an EPROM ... not a EEPROM. The only EEPROM that I know that has the same requirements (pin-wise) as the 27C128 is the Atmel 29C256 ... but, its 256K so you'll have to write the program into the upper half.

Tim

 

Which is very easy to do.

Don't bother with EPROMs, they're old tech. Flash is the way to go.

 

Ahh ok that helps a bit


So do you burn the bin twice? or 0/1 out the upper half or what do you do with the spare memory?

I'd like to go EEPROM

[edit] errr, i guess the blank space would be at the lower half?

 

Thanks btw

 

What I do is open a DOS windows and do a 'copy /b edited.bin + edited.bin burn.bin'

where burn.bin is the one that gets burned to the chip. This way I don't worry about offsets.

In the future I'll have two different bins that get copied together and a switch so that I can select between the two, but that's a long term plan.

 

What Alex said...

 

Ahh so basically doubling the file size, and filling the 256k..


So just out of curriosity which of the two DOES get used? the first half of the memory or the later half?

 

Upper half is used. You can really put anything in the lower half. The lower address space is for selecting other chips in the ECM.
J

 

sweet

thanks thats what i was lookin for

 

OOOpppss, I just remembered something. The lower half is not for selecting other chips. It is completely unused by the ECM.
J

 

Actually it's only 16K doubled to 32K... the 256k refers to bits, we usually talk about file sizes in bytes.

Just so you don't get worried when you download bins.