Re: New CBM-II discoveries

From: Steve Gray <*sjgray_at_rogers.com*> Date: Wed, 27 Jun 2018 00:31:44 +0000 (UTC) Message-ID: <272800632.3046273.1530059504419@mail.yahoo.com> · sjgray_at_rogers.com

it looks like the ports are mostly output. plus, we need to write the firmware anyway so it doesn't need to be compatible with anything.
Steve

      From: Michał Pleban <lists@michau.name>
 To: cbm-hackers@musoftware.de 
 Sent: Tuesday, June 26, 2018 3:35 PM
 Subject: Re: New CBM-II discoveries

Steve Gray wrote:

> The schematic says 6523 or 6525. Can you not replace these with the
> D8255 chip like was done on the 8088 card?

The biggest problem with the 8255 is that the direction of individual
bits cannot be changed (and then the direction of the while port is
changed, the port is reset as we discussed before). So it depends on hoe
the other ports of the 6523 are used?

Regards,
Michau.