Guys,
I just confirmed that my board is behaving the same way
as described by Ian and Rich.
Data Bus LED's all ON while system is running. When I stop
and single step the Data LED's operate correctly. Examine
Next works and RUN returns system to normal running
system.
I need some time to look into these issues. Hope it turns out
to be simple things.
On 03/ 2/15 09:23 PM, Ian McLaughlin wrote:
Gentlemen,
I finally got my board into my Northstar Horizon for testing tonight.
I can confirm that I am seeing the same thing as described previously.
RUN/STOP appears to operate correctly. RESET appears to operate
correctly. Single Step appears to operate correctly. I think EXAMINE
might be working (I can set an address, and EXAMINE and always get the
same value).
I'm not so sure about EXAMINE NEXT - each press seems to cycle through
4 different addresses (non-sequential) then go back to the starting
address.
DEPOSIT is definitely not working. I am unable to DEPOSIT a value into
RAM.
My setup - Stock Northstar Horizon. The Northstar CPU board has a
front panel connector which I have connected to the FP mini.
Jumpers - all combinations have been attempted, and I'm unsure what
the correct settings should be.
I can perform any debugging or testing if anyone can suggest what I
should be looking for. Otherwise, I will wait for others to see what
they find out.
Ian
On Mar 2, 2015, at 7:40 AM, Don Caprio <[email protected]
<mailto:[email protected]>> wrote:
Rich,
I'm having the same Examine problem with my board as well.
Josh had the last prototype working and all his mods went to the
schematic.
I need to go back and review our emails and make sure all the
changes got made.
On 03/ 1/15 03:05 PM, Richard Cini wrote:
A quick follow-up. I did some probing of the LS123 one-shots and I
discovered something interesting. Pin 12 (Q-prime) on both U17 and
U20 are free-running. The other one shots seem to be triggering
properly. I don’t see any immediate cause for this, so I swapped the
chips but I get the same result.
Rich
--
Rich Cini
Collector of Classic Computers
Build Master and lead engineer, Altair32 Emulator
http://www.classiccmp.org/cini
http://www.classiccmp.org/altair32
From: Richard A Cini <[email protected]
<mailto:[email protected]>>
Date: Sunday, March 1, 2015 at 4:29 PM
To: S100-Post <[email protected]
<mailto:[email protected]>>
Subject: MiniFP build - data bus question
Guys —
I finished my MiniFP board this morning and I can’t seem to deposit
to or read from memory using the EXAMINE toggle. The “next” part of
the function works, so I can step among addresses but the data LEDs
are all on all the time (unless I set JP5 SSW_DSBL jumper). However,
if I use the SINGLE_STEP switch, the data bus LEDs appear to reflect
memory contents.
The experimental system is very simple CompuPro RAM17 (64k), IMSAI
8080 board, and the front panel. Before I say that anything is
wrong, can someone confirm the jumpers? I think only the MWRT should
be jumpered. The RAM17 is an IEEE-696 board so as I do for my IMSAI,
I’ve isolated pins 20/70 (UNPROT/PROT) on that board.
Chip-wise, I’ve used LS (including the LS123 as recommended in the
Wiki) except the 7402. I don’t have any 7400’s in-stock so I’m using
LS00 for now…don’t know if that’s part of the issue since those
gates are used in the EXAMINE circuit. I replaced the 8212 just in
case, but that had no effect. The data cable is fine.
Any help, even questions to get me thinking, would be appreciated. I
feel I’m pretty close to a solution here.
Thanks!
Rich
--
Rich Cini
Collector of Classic Computers
Build Master and lead engineer, Altair32 Emulator
http://www.classiccmp.org/cini
http://www.classiccmp.org/altair32
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