|  From: Richard Atkinson 
Date: 2000-08-17 
Subject: Re: 1551 programming 
 |  
On Thu, 17 Aug 2000, Zsolt Prievara wrote: 
 
> I'm back with new questions. Has anybody documentation about the C1551 drive 
> internals functions? What commands can it accept at the $FEF0 ports? 
 
This would be very interesting to me too. The ROM is on Funet and I know the hardware that connects the 1551 to the main processor - but I have no idea what runs across that bus in normal kernal routines. Presumably it's another variant of the IEEE-488 protocol, but almost certainly cut down a lot from the original PET implementation. Perhaps it's an 8 bit data bus with a CLOCK line and an ACK line, similar to the 1541 but with a parallel data connection. This is pure speculation; I would be very interested to see real 1551 documentation, or even 1551 schematics. 
 
Richard 
 
-- 
Richard Atkinson Software Engineer Tenison Technology EDA Ltd http://www.tenisontech.com/ 
 |  
  |   |   
 Copyright © Plus/4 World Team, 2001-2025. Support Plus/4 World on Patreon |