memcal question:Multiple maps on one chip

[michaelw]

As far as I can workout (ie by reading the other threads)the 1227808 runs the 128kbit (16kB) rom. If you substitue a 256,512 or heaven forbid a 1 Mbit chip you can select the "program" by altering the extra address pins. Now what would happen if you could do this cleanly (no mechanical switches) whilst the car is running?

Would the ECU puke (very bad). Or would the map switch over fine?

I guess it boils down to does the memcal hold a program that the ecu executes (this wont work) or is it mearly a look-up table (in this case this has a good chance).

I can see a few reasons why you would want to have multiple codes on the one chip, for example
Map1)normal
Map2)fuel saving
Map3)fuel wasting
Map4)the kids have the car.

Mike

 

[hakhawk]

yep, it can be done, i am working on setting up one myself, so when my memcals, my programmer and my extra eproms turn up, i will try it and let you know, will be testing switching while car running and driving to see what happens. i wont be using mechanical switches though, i wil have a single button style thing setup that will switch them and have the switching control removeable so it cant be changed without it.

 

[michaelw]

With your car pc you could have all sorts of fun with "eprom emulators".

I was thinking of using debounced-non contacts switches (kinda like the ipod). You might like to look at www.futurlec.com for components.

I will await your success.

Mike

 

[yZoH]

hakhawk when your stuff turns up lemme know hehe *cough* eprom.... hehehe

Talk soon dude

Cheers
Mat

 

[hakhawk]

dont worry VnPheonixS, you'll know wen i do, and michaelw, i cant wait to get some emulation happening, but after i get the hang of tuning at the desktop, my circuit will involve one single push button, a seven segment led display to show what map its on and the rest is hush hush for now. but should be sweet as.

 

[VL400]

The memcal contains the code segement (running code) and calibration data (data lookups). Nothing is stored off the memcal as such for either of these. Make sure the code segement is the same for all the stacked bins and only the calibration data is different - the calibration data is what tunerpro changes. If the code segment is different then it would be very advisable to switch 'maps' with the engine/ignition off. So long as you use the same base memcal id (ie ASBY) for all the bins and it switches quickly and cleanly it shouldn't be a problem, just dont switch when its a critical time like WOT.

 

[michaelw]

Do you have a memory map of the memcal? It could be possible to split the code segment and the maps.

Mike

 

[VL400]

It depends on the ECU/PCM, for a VN memory is mapped like this....
RAM - $0000 to $01FF (Stack starts at $01FF and grows down)
<external hardware and internal registers are mapped in here>
Calibration Data - $C000 to $CFFF
Code Segment - $D000 to $FFFF

The two you are concerned with are from $C000 to $FFFF, which should have been obvious when using a 128k EPROM.

 

[Doctor Bob]

have a look at craig moates site, he has pre built switching gear
and yes provided the base image is the same it works fine switching while running.

Rob

 

[hakhawk]

yeh, but i cant afford his switching gear, hell i cant afford a predone memcal, thats why im going to try to do my own. but i must say, his site helped me design my switching setup. just waiting on my programmer, memcals and eproms to start playing.