ECU chipping.....

[datsunboy]

Hey people,Has anyone ever experimented with using the 256kb chips ( 27C256 ), and writing 2 different maps to it, so you can switch between them?

I have used a 27C256 chip before with the same maps in each half....and it has worked fine.

i found a site that explains how to switch between the 2 maps.....( but it was for mopar, not a Nissan. ). Has anyone tried doing this on thier CA?

it says to supply pin 27 ( A14 ) 5V or 0V to switch.

here is the link if anyone is interested.....http://www.knizefamily.net/rus....html

[Vetal]

I'm using this setup, works fine BTW, very sad you didn't ask this earlier, cause I was using 27C256, but in the link you gave it is said you can use 28C256 and not mess with UV eraser... Would save me a LOT of time

[datsunboy]

it is working???can you tell me exactly how you did it?

cause I atempted to, but killed one of my ECU's as soon as I hooked it it to 5V ( 12V, going into a 5V regulator chip ), then onto pins 27 and 28 ( because they are both joined on the board anyway ).is this how you did it?have you maybe got a photo or something?

I'd really like to get it working, as I have a mate who wants to run 2 maps....one for Supercharged, and one for when he's running it NA ( S/C has a electric clutch )

[Vetal]

Yes it's working perfectly You have to switch the last address pin between either ground pin or +5V pin (~Vpp or how it is called). Just get a pin diagram for 27C256 and everything will be clear P.S. If I made it now I probably would use 28C512 EPROMs to have 4 maps at once - would take slighlty less time to fine tune the car

[datsunboy]

I tried connecting pins 27 ( A14 ) and 28 ( Vpp ) to 5V ( it seems the are joined together on the circuit board anyway ).do you still have those 2 pins plugged into the ECU?....or have you isolated them first, THEN switched it to 5V or ground?pics of how you did it would be awesome how would you go about switching between 4 different maps?this would be good cause "d!ck smith" is discontinuing the 27C256 chips ......can't hurt to have more!lol

[datsunboy]

I have a pin diagram for both the 27C256 and 28C256

[Vetal]

I'll try to recall how I did it... Sorry no pics cause I spent some 20 minutes isolating all the wires

[datsunboy]

that'd be AWESOME if you could do that for me!

[datsunboy]

bump.....have you had a chance to remember yet?

[Vetal]

As far as I remember, on the chip side of the ribbon cable I either connected pin ~27 to either one of the ground pins, or to the +5V pin, and that made the EPROM to choose either lower or upper half of memory. Does it make it any clearer?

[datsunboy]

chip side of the ribon cable?....what ribon cable?so you ISOLATED pin 27 from anything else first....then wsitched it between a ground pin ( pin 14 )....or a 5V pin?

the factory setup has pins 27 and 28 connected together on the PCB....do I have to get rid of this?

the ribbon cable you speak of....did you add this yourself to remote mount the EPROM? ( ie not directly into the socket on the PCB )

[Vetal]

Yes I added ~30cm ribbon cable (from floppy drive I think) so I'm able to reach socket from drivers' seat to change EPROM's and switch between them.So all I did, I did not connect this last address pin but rather switched it to ground or 5V

[datsunboy]

ah.....ok...that makes a bit more sense!I'll give it a try next week and let you know how I get on!cheers for your help!

[Vetal]

That's where I first read about switching maps, and that's basically all zerothread?id=58059But I see you also read that thread I would say, as soon as you will hold the socket and the cable in your hands everything will be pretty clear

[Vetal]

datsunboy, I saw that you were making some research into emulators?

[datsunboy]

yeah a emulayor would be very handy.I found some plans on the net to build some, but havnt got around to it yet

[Vetal]

Do those emulators enable on-the-fly changing of the data?

[datsunboy]

pretty sure they do....heres the page if you want to check it out:http://www.web-ee.com/Electron...shtml