Swithable Eprom

[Ken Kelly]

Great Dave,
	I love simple solutions
		Ken

"David A. Cooley" wrote:
> 
> At 11:17 PM 5/13/99 -0700, you wrote:
> >I am a student and for a class project I am researching the best way to make
> >a switchable Eprom for a GM P-4 computer,  the normal Eprom is a 27c128, I
> >would like to have 10 different programs loaded for testing in back to back
> >conditions.
> >
> >If you could let me know the best way to do such a thing it would be
> >appreciated.  I did search the archive, but thought the information may have
> >changed since the 97 postings I found.
> 
> Ron,
> I did this with 6 programs back in 93 on a S15 Jimmy.  Used a 27C1024 and
> burnt the programs in order, IE prog 1 from 0 to 128K, 2 from 128K to 256K
> etc.  Hooked the lower address lines and all the data/power etc to the ECM
> like a 27C128.  The additional address lines I sent to a thumbwheel switch.
>  Used it to select the lines so the ECM saw whatever 128K block I needed it
> to see.  Could switch it while running down the road without a hiccup.
> ===========================================================
>            David Cooley N5XMT           Internet: N5XMT at bellsouth.net
>      Packet: N5XMT at KQ4LO.#INT.NC.USA.NA   T.A.P.R. Member #7068
>    Sponges grow in the ocean... Wonder how deep it would be if they didn't?!
> ===========================================================