24 Jul
2005
24 Jul
'05
4:34 p.m.
Subject: Compupro progress / Console questions ?
From: Dave Dunfield <dave04a at dunfield.com>
Date: Sun, 24 Jul 2005 11:06:07 -0400
To: cctalk at classiccmp.org
Hi Guys,
I disassembled the boot ROM, and rebuilt it with some output to
show what was reading from the FDC.
I determined that it was aborting the READ command with a "Drive
changed Ready State during command". I tested the SA-851 drives on
a different machine, but it appears they are incompatible with or
not jumpered correctly for the Compupro controller.
known but forgotton problem in the 8" world. 765 has a READY sense line
and the 851 is know for changing state of the line during select.
Solution, force ready at the board (jumper) and don't use it. READY
was for detecting disk changes.
According to Compupro Docs, the Console port is USER 7
- I have
setup the board to respond to users 4-7, which is the default setup
requireed for the console shows in the Compupro docs. As noted
above, I can select user7 and talk to the console correctly, which
would suggest that this is all working correctly.
It is likely initing the ports but may not use any of them. It's
possible the bootable media may use a different port scheme. Its
likely a difference between the boot roms and the BIOS code once
the boot transfers to the OS.
I assume based on the CPU your runnig CP/m-86 (or any DRI -86)
as the boot roms load a loader then load the OS (bios and all).
So booting is multi step code.
Allison