Re: ROM Dump of Amiga Keyboard controller

From: Segher Boessenkool <segher_at_kernel.crashing.org>
Date: Wed, 11 Jun 2014 10:35:38 -0500
Message-ID: <20140611153538.GA8231@gate.crashing.org>
On Wed, Jun 11, 2014 at 05:29:35PM +0200, Rainer Buchty wrote:
> On Wed, 11 Jun 2014, Gerrit Heitsch wrote:
> >External test equipment can use this feature to test internal CPU 
> >logic and I/O. A program can be loaded into RAM allowing the contents 
> >of the instruction ROM to be dumped to any port for external 
> >verification.
> 
> To me that -- optimistically -- confirms the "ROM-only" theory, although 
> admittedly the wording is very vague.

But then you cannot dump the ROM that way.

Many micros with a similar "load the program over a port" mode disable
that mode as soon as some jump instruction is executed (those do not make
sense when blasting in the insns anyway); maybe the 6500/1 does something
similar?  It shouldn't be very hard to try out all ops, see which ones
stop port fetch.


Segher

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Received on 2014-06-11 16:01:05

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