Re: Switchless ROMs

From: Michał Pleban <>
Date: Tue, 27 Dec 2016 00:23:16 +0100
Message-ID: <>

smf wrote:

> You do need to guarantee that your bank switch register powers up in the
> correct state. Which might be a little tricky with only the standard rom
> signals.

A small RC circuit will do the trick of supplying a reset signal upon
power up. Or, if you use a more complex circuit like CPLD, they always
power up in a known state. But...

> But yeah if you're only allowing a switch in your special kernel then
> you don't need any magic sequences, but I quite like the idea of being
> able to switch. It would for example allow you to create a kernel that
> has both tape and jiffydos routines in, with automatic switching between
> the two 8k images.

... but what I said is that you cannot switch KERNALs if you do not tap
into the RESET line. You power up into the switching KERNAL, you switch
once, and that's it until you power off. Magic sequences will not help here.


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Received on 2016-12-27 00:00:21

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