[BBC-Micro] Programatically "reset" a Beeb?

John Kortink kortink at inter.nl.net
Wed Aug 15 19:46:56 BST 2012


On Wed, 15 Aug 2012 13:44:50 +0100, Richard Gellman
<splodge at starfleet-net.co.uk> wrote:

>[...]
>
>I'm having trouble with a "reset" process. Hopefully someone
>here can point out the Bleeding Obvious(tm) to me. 
>
>[...]
>
>Store the bit in the ROM set select
>register (1MHz bus) 
>
>JMP (&FFFC) 
>
>Except, it doesn't quite work. It
>changes ROM set sure enough, but the start sequence is interrupted and
>scrolls uncontrollably, sometimes with characters on screen.
>
>[...]

Try :

LDA #&7F
STA &FE4E

or equivalent, before you do the

JMP (&FFFC)

The OS will then find the system VIA in a state that is
consistent with a power up, and acts accordingly.


John Kortink

-- 

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