switching between EPROMS

[Warren Crowther]

>     If you switch it with the engine turned OFF, I don't think you'd have 
>     a problem.

This is a simple solution, and will work, but..

I'd prefer to do it with the engine ON!!!  I don't see any reason why it
cannot be done, provided the switch over is not done at a critical time, and
that the only difference between the EPROMS is the data: ie. the fuelling,
ignition timing, etc.  Also it should be done quick enough so that the micro
does not miss an external data fetch (anyone know what the micro will do in
this case??  will it hang or retry? ).

Warren

>______________________________ Reply Separator
_________________________________
>Subject: switching between EPROMS
>Author:  diy_efi at coulomb.eng.ohio-state.edu at INTERNET
>Date:    8/28/96 3:04 PM
>
>
>Hello All,
>     
>quick question:
>     
>has anyone made a device that you can plugs lots of EPROMs into, plug into 
>your car ECU, and switch between them with a switch??
>     
>I want to make one for only 2 EPROMs, and was thinking of using a simple 
>switch to switch the chip enable between the EPROMs.  Will this work?? or 
>will the time gap when neither of the EPROMs are enabled be enough to 
>confuse the micro, and go into some unknown state?  
>     
>I could use latches and some simple logic chips to get around this I guess.
>     
>Any recommendations??
>     
>Warren
>_______________________________________________________________ 
>Warren Crowther      
>Software Engineer         DDI +649 3610625 
>warren at advgroup.co.nz            Ph  +649 3602834 x5625 
>Advantage Systems Ltd                     Fax +649 3764210
>     
>     
>
>
_______________________________________________________________
Warren Crowther (from home)     
Software Engineer    			  DDI +649 3610625
warren at advgroup.co.nz        		  Ph  +649 3602834 x5625
Advantage Systems Ltd                     Fax +649 3764210