Re: ROM Dump of Amiga Keyboard controller

From: Rainer Buchty <>
Date: Wed, 11 Jun 2014 18:18:56 +0200 (CEST)
Message-ID: <alpine.DEB.2.02.1406111808180.14285@localhost>
On Wed, 11 Jun 2014, Gerrit Heitsch wrote:

> No matter how, you will still have to return RESET to +5V before you 
> can read and dump the ROM. :)

Sure, but that could be done using one of the ports controlling e.g. a 
4053 to select either 5V or 10V as the RST voltage (assuming that 
there's not much current flowing, which mustn't be the case anyway when 
using a simple DC voltage doubler for the 5V->10V conversion).

When reset, the selecting is implicitly set to 0, then the first 
operations in RAM could be setting that port to 1.

> That depends on the target audience for the datasheet of course.

Sure. But those internal datasheets often enough don't make it into the 
wild as they are only supplied to a very limited set of customers such 
as manufacturers for programmers and test equipment where it might be 
somewhat easy to track back where it originated from.

After all, not getting (easy) access to the internal program is often 
enough part of the security model (and a reason not to chose 8048/51).

> Do you have a datasheet for that one somewhere?


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Received on 2014-06-11 17:00:03

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