chips?

[Aries_Turbo]

anyone know a good place for 27c256 or 28c256 eproms?

Ive found a few on ebay but I dont know exactly which part numbers are the right ones.

heres a few parts ive found.

m27c256b-15f1 (ST)

and

27C256-15 (Texas Instruments)

are these compatible with an 87 LM?
Thanks

Brian

[ShelGame]

You can get them from Moates.net or Mouser.com or digikey.com.

The -15 means it's 150ns chip. I usually get 120 or 90ns. Sometimes the 150's don't work in the SMEC (for me). I'm not sure about the LM.

[bn880]

Mouser seems pretty good, better selection than Digikey. Right, 120ns or less is a best bet.

[Aries_Turbo]

the thing I was concerned with was the "-f1" or the "b" after the 256.... I can get these two at about 1$ a pop. I was just wondering if those would work ok. they are on ebay.

there are so many different subscripts that sometimes I am wary about which one to get. I know that the number (-15 in this case) corresponds to the timing and I looked through the subscripts on the datasheets too see what the other stuff means (packaging and such) but I just wanted to ask before I purchased something that was different enough to not work. I just ordered the Willem enhanced from mcu mall so I'll be all set when that gets here. I just need some roms.

thanks

Brian

[csxtra]

Brian,

If you are looking for pin-compatible chips that will work in an 87 LM, try these Flash Chips:

http://www.mouser.com/search/refine....4-27SF5127CPGE

$1.45 each, in stock at Mouser, flash memory so they are eraseable/re-writable without having to play UV games, and they have been tested in an Omni running 10.80 @ 132.9, as well as a somewhat-slower CSX...

EDIT: I just saw that you are going to use the Willem Enhanced burner, which is what I have been using to erase/read/write these chips, so you should be good to go

[cordes]

Brian,

If you are looking for pin-compatible chips that will work in an 87 LM, try these Flash Chips:

http://www.mouser.com/search/refine....4-27SF5127CPGE

$1.45 each, in stock at Mouser, flash memory so they are eraseable/re-writable without having to play UV games, and they have been tested in an Omni running 10.80 @ 132.9, as well as a somewhat-slower CSX...

EDIT: I just saw that you are going to use the Willem Enhanced burner, which is what I have been using to erase/read/write these chips, so you should be good to go

Those are the same chips that I use in my car. There is no better way to do it IMO. No hassle of trying to setup your LM to be flashable, and they can't be had for much cheaper.

YOu can check out my LM custom cal how to on my site. It will walk you through putting a cal on an LM with the aforementioned chip. Pretty fool proof that way.

[Aries_Turbo]

cool, thanks guys. Warren, i have some more questions for you but I'll pm you.

Brian

[Aries_Turbo]

Oh btw... I do have a few M27c256b-12f6 chips in my posession but I couldnt get them to program correctly I kept getting some error that said something like "error at 0x000000 chip 0xff buffer 0x00" or something similar to that. any idea?

Brian

[Una]

Means the chip wasn't properly erased before you tried to burn it.. I often come across chips that give me problems burning or erasing them. I have a pile of about 50 still, so I just chuck 'em in the trash and grab another..

[bn880]

Just as a sidenote (not really), you should get industrial or military versions of chips, usually -i or -m

As your car will see a wide range of temps and the eproms you are getting just might break... not likely but is it worth the $4?

I can recommend 698-cat28c256li-12 from mouser. Not directly pin compatible but requires one pin swap

[bn880]

Oh btw... I do have a few M27c256b-12f6 chips in my posession but I couldnt get them to program correctly I kept getting some error that said something like "error at 0x000000 chip 0xff buffer 0x00" or something similar to that. any idea?

Brian

Yep, you have one of 2 types of those

1. Non erasable. (you can write all bits down to 0 but never back to 1)
2. UV erasable

With 2 you are in luck, take off the sticker if any, set em out in the sun for aday. Or get a UV bulb and UV sun glasses.

[cordes]

Yep, you have one of 2 types of those

1. Non erasable. (you can write all bits down to 0 but never back to 1)
2. UV erasable

With 2 you are in luck, take off the sticker if any, set em out in the sun for aday. Or get a UV bulb and UV sun glasses.

I have read that it would take about 10 years or so to erase a chip by exposure to ambient sunlight. Does setting them in the sun really work?

[bn880]

Ahh yes, it may take a few weeks apparently. I never did that just heard about sun erasing from some colleagues. Anyway the UV bulbs aren't that expensive.

[bn880]

I can recommend 698-cat28c256li-12 from mouser. Not directly pin compatible but may require one pin swap

Just making a note on myself that those chips are kick a** but *might* require you to swap pins 1 with pin 27. (when installing zif for example) However the LM probably holds all these pins at VCC anyway... so no change needed anyway. (My 87 TII lm is not currently accessible or I would tell you 100%)

[Una]

I use a toothbrush holder with a germicidal UV light in it to erase my chips, cost me a wopping $13 shipped online..

[bn880]

Just making a note on myself that those chips are kick a** but *might* require you to swap pins 1 with pin 27. (when installing zif for example) However the LM probably holds all these pins at VCC anyway... so no change needed anyway. (My 87 TII lm is not currently accessible or I would tell you 100%)

Just tried this on the programmer, the only thing that you have to do with a 28C256 is program the second 128K not the first, so enter an offset of 4000h in the willem programming software and voila, what happens is the LM holds pin 1 high thinking it's VPP of 27128, what that does is it puts a high on A14 of the 28C256, essentially reading only th second half of the EEPROM. You can also cut that lead and install a switch to toggle between 1st and 2nd half of the EEPROM for 2 different cals.

[bn880]

Dang! Tried those 28C256 chips in the 87 TII LM today, and no cals worked at all. Neither at 0000h nor at 4000h! And I had stock cals at those addresses.

The stock 27128 chip still works in the LM, so... I'm thinking there is either a checksum fault or these 28C256-12 chips are really not compatible timing or voltage wise... worked fine when testing on the burner in 27128 read mode...

(Can't do too much testing as the car is far away waiting for a steering rack/hoses...)

[Una]

27fs512 Flash eprom chip, directly compatible in 27c128 or 27c256 computers..

[bn880]

Well apparently as directly compatible as 28C256 when programming to 4000h... I've seen on D-cal and elsewhere that 28C256 is indded mant to work even without any mods, could be wrong, but i looked at the data sheets in great detail and ... I'm just baffled ATM as to why it isn't reading the 28C256 at 4000h.

Did you mean 27128 not 27c128?

[Una]

Only the idiots said it was directly compatible. Those of us that know our stuff never said that. It takes a helluvalot of modification to make one of those fly in a SMEC.