Timing-critical chips for replica Front Panel?

[Chuck(G)]

See my suggestion under "8088 pinouts" for running an analog voltmeter to measure instructions/seconds. You can use the Z80 M1 signal for that...

[RickNel]

Hey Chuck - I didn't realise this forum hosted threads for interior decorators

Seriously though, I think there is plenty of scope (excuse the pun) to develop better visual diagnostic cues for the carers of ageing machines. My S-100 box is blessed with one simple power LED that tells me nothing at all about the machine beyond the power switch. Hence my interest in an external Front Panel and possibly export of full set of bus signals to the PC environment for more useful visual display.

But I like your "tachometer" idea. Swingenpoints as well as Blinkenlights!

Rick

[Chuck(G)]

Hey, my old Integrand S100 box has a reset button on the front panel. That's it--not even a power switch (it's on the back of the system). Not even a "power" indicator. The folks at Integrand were into pure brute functionality (it's a great box, BTW, with a huge power supply and lots of slots).

A front panel would be pretty cool, but totally un-authentic on it.

A couple of the old GE mainframes had a "thousand operations per second" analog meter on the operator's console (the fact that it was a mainframe by GE tells you how long ago that was!).

[Chuck(G)]

There were some very sexy front panels out there during the 60s and 70s. Honeywell had some of the best.

I recall seeing a magnificent operator's console on a water-cooled system at Honeywell's Phoenix plant sometime around 1975. This had not only blinkenlights and CRT displays, but Burroughs self-scan neon bar graph displays to show activity in various parts of the system. These big orange bars bouncing up and down as the machine did who-knew-what.

It's a shame, but other than the H200 and H316 and the H316 "kitchen computer", I can't find any images of Honeywell consoles on the web. The web barely turns up mention of Burroughs "Self Scan" displays.

[billdeg]

If you have an "in circuit emulator" you can interface with the processor and the memory that way, kind of like a front panel. You can see where the bootstrap is loaded, if there are PROMs you can check the memory range for the Proms to verify the code is loaded, run memory card tests, etc.

I used one earlier this year to test an S-100 without I/O or a front panel to determine the operational status of the cards, etc.

Not sure who sells an "ICE" for your processor, or how expensive it'd be, but this will work.

Bill

[RickNel]

Bill - there are plans and instructions for a Z80 ICE available here:

http://www.tauntek.com/Z80-In-Circuit-Emulator.htm

I'm involved in a project to build a replica Front Panel but am also mulling whether to put together a Z80 ICE like this one.

One of my system problems is a corrupted IPL ROM and no source code for it. So ability to intercept and debug the IPL is pretty challenging when I'm not sure what other hardware bugs might be causing trouble on any of 4 cards (I/O, CPU, RAM and FDC) that all have to be working for the IPL code to even load a working BIOS and CCP. I might need both tools plus lots of imagination.

Rick

[billdeg]

Rick,
I have one of these, it works great and I recommend it if you can build one. I use it regularly for Z80 system diagnosis. I was able to get into a system when no other approach worked.

I was also involved in the testing of this device and I made some suggestions that were implemented in later versions. I did not design it however. I was just a tester.

Bill