Re: What is the most used ROM in the brown 1541?

From: Spiro Trikaliotis <ml-cbmhackers_at_trikaliotis.net>
Date: Fri, 19 Jun 2015 22:13:32 +0200
Message-ID: <20150619201332.GA32395@hermes.local.trikaliotis.net>
Hello Ruud,

* On Fri, Jun 19, 2015 at 08:08:56AM +0200 Ruud@Baltissen.org wrote:
 
> > The 4040 used 8 bytes. Anyway, it used 8 bytes before conversion to GCR,
> > which was done in hardware. Thus, the gap was 8 * 10 bit = 80 bit long.
> > 
> > The 1540 just reused the value 8. Unfortunately, here, it is 8 *real*
> > bytes, resulting in a gap of 8 * 8 bit = 64 bit.
> 
> To be honest, I have my doubts about your statement. But I first 
> have to disassemble the ROMs of the 4040 and to have another look at 
> the schematics before I can give a scientific reaction.

Now you got me surprised at first. I wrote it from memory, but I was
sure that it was correct.

Thus, I tried to find a proof for my statement. Unfortunately, until
now, I have not even re-found the format routine on the 4040. ;) Even
worse, on the schematics I found on zimmers.net, I did not even find the
GCR conversion ROM.

I am a little bit puzzled now. I cannot believe that my memory played
tricks with me. :(

On the other hand, I am not completely sure that I did not overlook
something today. I will have to re-investigate. Of course, if you are
faster than me, I would be thankful if you can tell me if my statement
was right or wrong.

Regards from a very unsure
Spiro.

-- 
Spiro R. Trikaliotis
http://www.trikaliotis.net/

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Received on 2015-06-19 21:00:07

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