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Memodyne M-80 'Computer'?

falter

falter

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Bought this last minute. I did a bit of cursory reading last night and couldn't find too much info other than some references to use as a data recorder for scientific projects. However the 'm-80' referenced in those was different.. had a front panel with controls for the tape.

I thought it was just a specialized tape drive, but the fact that the final word in its name is 'Computer' and the presence of a Reset switch in addition to power kind of has me thinking it is some kind of computer. And indeed, some of the docs I found said it had a Z80 in it.

Anyone ever heard of these?

http://www.ebay.com/itm/401107211451
 
Looks to me like a digital cassette drive, usually used as a replacement for paper tape. Used to be very common in the CNC world.

I had a Techtran unit like that, but with dual cassettes. Had a high-speed search function in addition.

The idea of an add-in 64KB Z80 CPU is interesting, but your I/O options will be limited.
 
It arrived. That was fast!

20160430_125603_resized.jpg

Inside there is a pretty substantial looking power supply, and a 'motherboard' with several cards. Here are the ones I could get out of it:

20160430_124924_resized.jpg 20160430_125002_resized.jpg 20160430_125206_resized.jpg 20160430_125254_resized.jpg

20160430_125111_resized.jpg 20160430_132249_resized.jpg

So it appears to have not one but two Z80 cpus. The cards closest to the tape drive are separated from the others by a metal barrier. The chassis has a date of mid 1978 stamped inside.

I assumed the ports on the back were RS232, and tried hooking up via Hyperterm to see if anything lit up when the machine was turned on, but no dice thus far off either port. So either I have the settings wrong, those aren't serial ports, or the unit itself isn't working.

I'm guessing some kind of Z80 computer -- has CPU, RAM, some kind of EPROM, etc..
 
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I'm only seeing one Z80 CPU -- the other 40-pin device is a Zilog SIO, which is a serial controller. From the looks of it, I'm guessing Chuck is right and it's a cassette based "Tape Twin" style paper tape replacement/emulator. Looks like there's only 1K of RAM (2x 2114 compatible devices on the CPU board). Still very neat though, and I bet you could add RAM onto it and have a cassette-based computer system with little effort. Or you can use it as-is for data storage.
 
I found a bit of info on this machine:

"The M80/2000FPC and M80/3000FPC Systems combine a patented high-speed digital cassette recorder with a general purpose Z-80 based computer to perform a wide variety of tasks. The systems can operate as intelligent digital cassette recorders handling continuous data streams at rates up to 9600 baud, as standalone computers with a full 64K-byte, Z-80 memory capacity residing on an M80 Spare Card or, by combining the two preceding functions, as intelligent recording peripherals."

Sounds like it's a bit of both. I'm not sure how one would use it as a 'regular' Z-80 computer. I can't figure out how to get it to talk to any of my serial terminals. The eprom has '1200 baud' written on it, but I don't know if that's the serial port speed or what. And then no idea what bits to set, parity, etc.

I'm also not sure what the deal is with having two ports on the back, male and female DB25.. not sure which would be the standard RS232.

Interesting little unit though.
 
As I said, think of this as a substitute for a paper tape reader/punch. Very common in the CNC and embroidery world before similarly-equipped floppy boxes took their place. RS232 (judging from the 1488 and 1489 chips) in and out, via the two connectors. Normal function would be as a pass-through; when certain codes are received, can activate the cassette deck. (I'm thinking X-on and X-off).

You don't have much of a general purpose "computer", judging from the photos. You've got a Z80, with SIO serial chip and a CTC for BRG. EPROM for firmware and 1KB (2x2114) of RAM. The other boards seem to be related to the operation of the tape transport. Perhaps there was an option for more RAM and EPROM, but it's not here.

Since the CTC is the BRG, that EPROM almost certainly sets the data rate to 1200 bps; I'd start with 1200 E71 to begin with.
 
@snuci

I don't think the two are related. The NASA paper describes an incremental recorder (i.e. driven by stepper); you could see those on old key-to-tape systems where the 1/2" tape drive capstan was driven by a stepper; one step per fame.

This unit, I suspect uses plain old DC motors like a lot of its relatives. RS232C I/O. Here's one such for Mitsubishi CNC gear.
 
Chuck(G) said:
Could be, but there were several producers. Have a look at this 1976 Ad for Techtran. Very typical of these units--I owned one of these back when. Uses audio cassettes, but records 2 tracks of clock+data digitally. I think I still have some NCR data cassettes kicking around.
Click to expand...

Nice read on the ComputerWorld issue. Geez, I was still in the Navy and working on the Varian 620i about that time.
 
For the young 'uns among us, that particular CW gives a pretty good picture of the world in 1976. Note that there's scarcely a mention of "microprocessors" in that issue...
 
I'd just like to find something that explains how to make it operate. Ie. How you issue commands, etc. Still googling and hunting around.
 
Chuck(G) is absolutely correct. I've used these in the past, identical.

It's RS-232.

No recollection of how to use them, unfortunately. If you can find the manual for a Mitsubishi M-Plus control, it propapry tell you ull ubout i7. But those manuals are rarer than hens' teeth since Meau took them off their website. It won't help you anyway, probably, because these things were custom made to work with different controls, and no indication of which one.

They were a pain to use. IIRC, they rarely worked after a few years.

I wouldn't want one at home. But then I've already got a CNC with a dead tape drive!
 
Oh and if it is set up for a Mitsubishi, good luck getting a PC to talk to it without writing your own software. Mitsubishi used stupid, uncommon serial settings, and used different settings and handshaking for send and receive.
 
No, the stuff in the Byte issue are hobbyist-type early audio cassette interfaces. I used one myself back then, cobbled from the innards of a Novation modem and cheap GE cassette recorder. 300 bps, but it worked very well.

The Memodyne type is a paper-tape replacement and uses traditional saturation recording.
 
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