6800 opcode $02

[Allison]

>
>Subject: Re: 6800 opcode $02
>   From: "Dwight K. Elvey" <dwight.elvey at amd.com>
>   Date: Wed, 31 Aug 2005 09:44:34 -0700 (PDT)
>     To: cctalk at classiccmp.org
>
> 
>Hi
> On the 8080, one just has pullups on the bus and
>it will do continuous restart interrupts. This
>will cycle through the addresses for the push part of
>the instruction. This is handy for testing address
>decoders, especially when working with boards of
>unknown design.
> I wasn't aware that the 6800 had a similar method.
>Dwight
>

Not quite the same.  The 8080 RST (also works for z80 and 8085)
will revert to normal operation if rom(or any instruction source)
is encountered.  The HCF required hard reset to escape as it 
was not a useful instruction.  Hence the name Halt and Catch Fire.



Allison