[Coco] HD63x09 Question

[jdaggett at gate.net]

Robert

That is easy. Put a vector at $FFF0/1 and have it do one of  a 
couple of things. One being a vector to a service routine and read 
the MD register and display some info. Secondly it can be a vector 
to a soft reset. Or some other.

james


On 5 Jan 2005 at 17:18, Robert Gault wrote:

Date sent:      	Wed, 05 Jan 2005 17:18:32 -0500
From:           	Robert Gault <robert.gault at worldnet.att.net>
To:             	CoCoList for Color Computer Enthusiasts 
<coco at maltedmedia.com>
Subject:        	Re: [Coco] HD63x09 Question
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> One thing to watch out for with the 6309 is how it handles illegal
> opcodes. The 6809 just ignores them and skips to the next instruction.
> The 6309 vectors to a bad opcode trap. If there is no trap set, it is
> never-never land. As a divide by zero is also considered in this
> group, bad math can require a reboot. So, make sure you include some
> type of error vector recovery in any code specifically for the 6309.