Multicart game selector circuit?

I am interested in building a "selector" gadget for devices that take
jumpers
to select a program, such as this game cartridge where you have 5
jumpers
to select program #0-31 (the jumpers represent the binary number):

http://www.retroblast.com/Misc/Vectrex.php
http://www.retroblast.com/images/stories/Image/rb_archive/photos/vectr...Vectrex(4).JPG
http://www.retroblast.com/images/stories/Image/rb_archive/photos/vectr...Vectrex(12).JPG

The selector would have two 7-segment LEDs that display the currently
selected program number (0-31), and a couple pushbuttons (+/-) that
let you
increase/decrease the program #. The device translates the number
into
binary and turns on/off the appropriate switches or relays which are
attached to the jumpers on the device (ie multicart).

Or I would even like to build a kind of analog to digital converter
device which has a potentiometer (for example 100k) which gets
translated
into an 8-bit number (0-255) and 8 switches get opened/closed that
represent the value of the pot. Adding three 7-segment LEDs to
display
the current value in decimal would be cool and then it could be used
as a generic selector.

Does anyone know of any plans or schematics out on the Web to
construct
something like these? (For now I just wire switches to the jumpers.)

Thanks.

On Jan 25, 9:05 am, mad.scientist... DeleteThis @gmail.com wrote:
> I am interested in building a "selector" gadget for devices that take
> jumpers
> to select a program, such as this game cartridge where you have 5
> jumpers
> to select program #0-31 (the jumpers represent the binary number):
>
> http://www.retroblast.com/Misc/Vectrex.phphttp://www.retroblast.com/im...s/stori
>
> The selector would have two 7-segment LEDs that display the currently
> selected program number (0-31), and a couple pushbuttons (+/-) that
> let you
> increase/decrease the program #. The device translates the number
> into
> binary and turns on/off the appropriate switches or relays which are
> attached to the jumpers on the device (ie multicart).
>
> Or I would even like to build a kind of analog to digital converter
> device which has a potentiometer (for example 100k) which gets
> translated
> into an 8-bit number (0-255) and 8 switches get opened/closed that
> represent the value of the pot. Adding three 7-segment LEDs to
> display
> the current value in decimal would be cool and then it could be used
> as a generic selector.
>
> Does anyone know of any plans or schematics out on the Web to
> construct
> something like these? (For now I just wire switches to the jumpers.)
>
> Thanks.

Why complicate this bank switching process so much? IMO, the most
elegant solution is the menu selectable circuit in Sean Kelly's
MultiCart. Minimal hardware, easy to use. I haven't reverse
engineered his hardware setup but I suspect that he just has a simple
register at some writable address location. That is hooked up to
EPROM's upper address bits. His menu code then writes to that register
selecting the appropriate EPROM address block. While not perfect as
it is now, I'm sure that the code and circuit could be further
refined.

Peteski