Re: New CBM-II discoveries

From: Jim Brain <brain_at_jbrain.com>
Date: Fri, 6 Jul 2018 12:42:26 -0500
Message-ID: <a931d60e-b1d5-0cd0-6344-d028e32f4bc5@jbrain.com>
On 7/6/2018 12:10 PM, smf wrote:
> On 05/07/2018 11:34, Michał Pleban wrote:
>> You have a valid point, but considering how unlikely is it
>> that someone would write another IPC protocol for the board, we decided
>> that using another chip had less downsides.
>
> You gave up the fun of creating a 6523, made it harder to write new 
> software, it's an extra intel chip in a commodore machine and you've 
> set a precedent:
>
> "Can you not replace these with the D8255 chip like was done on the 
> 8088 card?"
>
> What were the downsides to recreating a 6523?
>
>
I protest the direction you're taking the discussion.  This seems less 
like a valid debate and more like a troll attempt.

  * No one was doing anything in this space before Michal did some work
  * While a dual 6522 approach would no doubt work, layout was eased by
    using the 8255.  Since it was already an Intel card, an 8255 is at
    home on the board.
  * He reworked the card to use a 8255, and modified the ROM to use the
    new IC

I believe he also put up the original schematics and PCB files, for the 
version that uses a 6523.  So, if another person wants to build the unit 
with a 6523, they can.

Arguing with the person who did all the work and trying to convince him 
that his goals were less admirable than yours will not have a successful 
outcome.

We should congratulate Michal for taking the time to update the design 
for a 30+ year old machine to use an OS that is equally old and no 
longer current.  Arguing over the choice of I/O IC seems overly petty in 
context.

Jim

-- 

Jim Brain
brain@jbrain.com
www.jbrain.com
Received on 2018-07-06 20:02:08

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