RE: rex combi card
Date: 2004-09-26 10:01:55

Zitat von "Baltissen, GJPAA (Ruud)" <>:

> A14 is used to tell the EPROM wether to use a module or a Kernal. This
> leaves us A13 to choose from one of the Kernals/modules. The problem is that
> when choosing Kernal 1, you get Module 1 'for free': there is no way to
> combine K1/M2 or K2/M1.
> IMHO you are better off with seperate EPROMs for both the Kernal and Module.

With seperate EPROMS you're just wasting space on the board which you don't 
An AND between the "old" Chipselect-Signal from the Kernal Socket and the Pin11 
RomL signal will be your new chipselect signal for a single Eprom.
The perfect chip to multiplex between several lines is a 74LS157.

On Digital Dungeon you can find my new file, "8kernals_8modules.txt". It 
describes how to switch between 8 kernals and seperate 8 modules (independant 
of each other) only using a 271001, a 74LS157, a few pullup-resistors and 

It works fine.

So long


Ein Service von

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