For those that know about ECU chipping, what kind of chip can be used? I know the 27C256 is commonly used, but if I get a higher capacity such as the 27C512 or higher, will it still be alright?

Thanks

 

the 27C512 will work, but you need to burn the rom in both the upper and lower memory sections. That means in your rom burner program, open the rom you want to burn. Then put that same rom in the buffer to burn, but set the start address at 8000h. That will put the first rom in the first 256kb of the chip and the second rom, which is the same, in the second 256kb of the chip.

The reason for this is that the 27C512 chip uses one of the pins to select the upper or lower memory locations, those being the 256kb sections you put the roms in. The ecu doesn't expect to have to control that pin, so the logic state isn't really defined. The ecu could be looking at the upper memory location, and if nothing was there, it would see a blank chip.

A twist on this, as you may be thinking, is to put a switch on that pin to select the different memory locations. That would allow you to have 2 completely different programs that you could switch between "on the fly". You would have to cycle power to the ecu when you switched it, obviously, but it's faster and more conveniant than pulling the chip.

There is more on this at http://www.pgmfi.org

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by drdisco69 &raquo;</TD></TR><TR><TD CLASS="quote">the 27C512 will work, but you need to burn the rom in both the upper and lower memory sections. That means in your rom burner program, open the rom you want to burn. Then put that same rom in the buffer to burn, but set the start address at 8000h. That will put the first rom in the first 256kb of the chip and the second rom, which is the same, in the second 256kb of the chip.

The reason for this is that the 27C512 chip uses one of the pins to select the upper or lower memory locations, those being the 256kb sections you put the roms in. The ecu doesn't expect to have to control that pin, so the logic state isn't really defined. The ecu could be looking at the upper memory location, and if nothing was there, it would see a blank chip.

A twist on this, as you may be thinking, is to put a switch on that pin to select the different memory locations. That would allow you to have 2 completely different programs that you could switch between "on the fly". You would have to cycle power to the ecu when you switched it, obviously, but it's faster and more conveniant than pulling the chip.

There is more on this at http://www.pgmfi.org </TD></TR></TABLE>

Sweet that's what I wanted to know here's one I found too.

http://www.moates.net/document...id=20

I got a question though. On moates it says the offset is used to place the buffer file at the end of the chip. When you said It places it on the first half of the chip and then puts a voltage on pin # whatever to specify the other half?


EDIT: Where'd you see how to set offsets on PGMFI? I couldn't really find anything.


Modified by V8MeatHead at 7:57 PM 5/10/2005

 

When they say end, they mean it like I do, the "beginning" 32KB and the "end" 32KB. You can see in that table that they still specify putting it at 8000 offset. Since the rom size is half of the chip size, you really only have 2 choices on where to put it, the beginning or the end.

I did a bit of searching the forums to find this info, I'll probably post this in the wiki there, as it seems to be fairly accurate and somewhat helpful...

Hope this answers your questions.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by drdisco69 &raquo;</TD></TR><TR><TD CLASS="quote">When they say end, they mean it like I do, the "beginning" 32KB and the "end" 32KB. You can see in that table that they still specify putting it at 8000 offset. Since the rom size is half of the chip size, you really only have 2 choices on where to put it, the beginning or the end.

I did a bit of searching the forums to find this info, I'll probably post this in the wiki there, as it seems to be fairly accurate and somewhat helpful...

Hope this answers your questions. </TD></TR></TABLE>

damnit i just posted my crap did I write it out correctly!? Maybe i have it backwards.

 

Oh, have you posted something there? I haven't even looked yet. If you have something there I'll take a look and see what you put. What section is it under?