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Tandy Memorex Vis specs

A

AlexRetro

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Hi all,

In google there is no about the ultra rare console/PC, it is really forgotten one.

My Mitsumi cdrom is broken after 20 years vacation. I would like to repair.
I think good idea to reverse hardware and to produce a emulator prototype.
Chinese guys can make any PCB but they need a specs and pinout what to make.

Maybe someone touch it and has documentation?
Please don't advice to ask Mitsumi, I had already done they lost any tech docs. MD2500 was the epic failure.

What I found:

CPU: 12 MHz 80286 AMD (N80L286-12/S)
FPU: 80287 Co-processor
Chipset: NCR Corporation, LSI Logic (X07901200, X04990200, X04990300)
RAM: 2 x 256k@4bits Samsung DRAM (KM44C256CJ7)
Video: Cirrus Logic (CL-GD5200-80PC-A) ("Tandy ADAC-1")
Audio: Yamaha 16-bits (YMF262-M). Adlib Gold compatible, not Sound Blaster compatible.
CDROM: Mitsumi (CRNC-FR002L)
Controls: Wireless infrared joypad
OS: Microsoft Modular Windows (based off Windows 3.1)
Memory: 1 MB ROM

CRNC-FR002L is not classic IDE , it is custom Mitsumi 40-pin connector.
https://old.pinouts.ru/HD/CdRomMitsumi_pinout.shtml says Mitsumi had 2 pinout "IDE" variants then after 1996 they got common IDE
I don't know which Vis uses.
 
There's a few things out there...

github.com

GitHub - TJBChris/memorex_vis: Misc. tools, utilities, and other goodies related to the Memorex (Tandy) Video Information System.

Misc. tools, utilities, and other goodies related to the Memorex (Tandy) Video Information System. - TJBChris/memorex_vis
github.com github.com
github.com

GitHub - hexbus/memorex-vis-homebrew: Memorex VIS Homebrew Getting Started Guide

Memorex VIS Homebrew Getting Started Guide. Contribute to hexbus/memorex-vis-homebrew development by creating an account on GitHub.
github.com github.com
www.youtube.com

TJBChris

You've found my little corner of the Internet. Here at YouTube's kids' table, I have the freedom to explore and share my love of all things Tandy/Radio Shack. I grew up on Tandy computers in the 1980s. Ever since I was a kid, I wanted to experience Tandy's machines that were beyond my reach...
www.youtube.com www.youtube.com

We're just starting to understand the platform and creating homebrew/developing for it. So, knock your socks off when it comes to contributing! :)

I'd love to get someone to help me adapt the BlueSCSI firmware to emulate the CD Drive in this thing (shouldn't be too hard) and then build an adapter to the 40 pin Panasonic interface (i.e. replace the SCSI Engine with a Panasonic CDROM engine) and send wifi-based images over to it for a dev-type environment. Feel free to contribute to the vis-homebrew Git repo.
 
It might be worth trying to wrangle some sort of ATA/ATAPI IDE compatible interface...

Then you would be able to attach almost any standard CD drive for a PC and also use other emulator hardware, like ZuluIDE

Essentially you want a hardware *bridge* that can speak both protocols.

-----

From the pinout you linked, it looks like the Mitsumi drive might be something you hook directly to the system bus... Sort of like if you jammed a custom ISA card into your external drive and then ran a bus extension.

+ A0, A1 -- Address Bits (2)
+ DB7, DB6, DB5, DB4, DB3, DB2, DB1, DB0 -- Data Bits (8)
+ WE, RE, EN -- Write Enable, Read Enable, Bus Enable
+ DRQ, DACK -- Data Request, Data Acknowledge (DMA)
+ INT -- Interrupt

Regular ATA/IDE is usually 16-bit data plus control signals and communications are at least partly register-driven. It also apparently utilizes 3 address lines -- Looks to be an I/O driven interface.

 
Last edited:
It would probably be worth looking at the driver for the cd drive to see how it interacts with the interface card.
 
Istarian said:
It would probably be worth looking at the driver for the cd drive to see how it interacts with the interface card.
Click to expand...
We already sort of know this - https://www.chiark.greenend.org.uk/~theom/electronics/panasoniccd.html
This (last message) has some information: https://forum.vcfed.org/index.php?threads/matsushita-panasonic-mke-cd-interface-specification.43700/

If we take something like a Blue SCSI (that already implements the SD interface, ISO interpretation, and Wifi interface) and just change the engine to a Panasonic engine from the SCSI engine, all we need to do is rewire the DE25 connector (at least on the devices I have) to the 44 pin connector. Something like this:

1778081906116.png

And maybe add one of the pins (maybe the DBs pin9 - normally SCSI parity) with a button to cycle to the next ISO image for now.

I think the protocol noted above is probably enough to get started if I can find someone who can handle the PIO programming of the Pi Pico and help get that started. We can reuse the bulk of the work that the community has already done and make this adapter and the framework from the BlueSCSI and get a kickstart, so to speak. That's my idea at least, if someone wants to help.

We can figure out the expansion connector next, but this might be a good way to start getting stuff on the device easily without making a lot of coasters.
 
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Do you have any other sources on the pinout for the Mitsumi drive/interface?

It looks like the Panasonic one presents status bits on a few interface lines and the Mitsumi pinout linked doesn't have those at all.

I feel like you're assuming a lot here on compatibility, but I certainly don't have any VIS hardware. So best of luck with your efforts.
 
Istarian said:
Do you have any other sources on the pinout for the Mitsumi drive/interface?

It looks like the Panasonic one presents status bits on a few interface lines and the Mitsumi pinout linked doesn't have those at all.

I feel like you're assuming a lot here on compatibility, but I certainly don't have any VIS hardware. So best of luck with your efforts.
Click to expand...
Apologies - I think I linked to the wrong bookmark - you're right, the Mitsumi one is different than the Panasonic one, and this is most definitely a Mitsumi drive. It's the predecessor to the LU-002S and LU-005S drives.

The Linux drive (mcdx) is here: https://git.whoi.edu/dgiaya/linux/-/blob/v2.6.18/drivers/cdrom/mcdx.c (This is the newer multisession one)
I believe the older non multisession driver is this one: https://git.whoi.edu/dgiaya/linux/-/blob/v2.6.18/drivers/cdrom/aztcd.c

Mitsumi Pinout: https://allpinouts.org/pinouts/connectors/data_storage/cd-rom-mitsumi/

This is the only mention of the FR drive that I can find: http://ubuntu.mirrorservice.org/sites/ftp.cdrom.com/pub/cdrom/drives/mitsumi.txt (It's at the very bottom) - note that it's February 1993 that Computer Shopper mentioned them.

Article 7851 (10 more) in alt.cd-rom:
From: wlsmith@valve.heart.rri.uwo.ca (Wayne Smith)
Subject: Mitsumi CD-ROM drives: ->Specification Listing<-
Organization: (this space for rent)
Date: Wed, 10 Feb 1993 21:56:33 GMT
Message-ID: <1993Feb10.215633.2167@julian.uwo.ca>
Sender: news@julian.uwo.ca (USENET News System)
Nntp-Posting-Host: valve.heart.rri.uwo.ca
Lines: 99

Contrary to popular belief :) it seems that Mitsumi can be quick when
responding to *potential* customer requests for information. 45 minutes
from first phone call, to answering machine, to personal response, to
fax-in-hand is not too shabby.

Anyways, here are the contents of a 6 page fax that desribes the
CRMC-LU005S and CRS-UF series Mitsumi CD-ROM drives...

----------------------------------------------------------------------------
Cover-page
Mitsumi CD-ROM DRIVE CRMC-LU005S
Printed in Japan, Sept/1992

MPC-Compliant and Photo-CD symbols are shown on this page, along with a
picture of the internal-type drive.
----------------------------------------------------------------------------
Specifications: CRMC-LU005S

Disc: CD-ROM Mode 1/Mode 2 and CD-Audio disc
Disc format: CD-ROM format (ISO 9660 and Yellow-book)
Disk Capacity: 12 cm Mode 1: 540B bytes
12 cm Mode 2: 630M bytes

Data Transfer rate: Mode 1: 150K bytes/sec
Mode 2: 175K bytes/sec
Burst: 1.6M bytes/sec

Access Time: 12 cm disk, 1/3 stroke: 350 msec Ave.
12 cm disk, full stroke: 650 msec Ave.

Error rate, mode 1: 10 exp -12
Interface: Mitsumi interface
Power requirements: 12V/.3A (1A peak), 5V/.4A

Audio: THD @ 1khz: 0.04%
Dynamic range @ 1khz: 92 dB
Channel separation @ 1khz: 87 dB
S/N ratio @ 1khz: 94 dB
Frequency response: +.5/-3 dB (20Hz to 20 khz)
Line out voltage: 0.78V rms
Headphone out voltage: 0.6V rms

Weight: 1.4 Kg
Operating condition: 0 C to 50 C, 20% to 85% relative humidity
Storage condition: -30 C to 60 C, 10% to 95% relative humidity
Operating life: POH: 25000 hours (POH ?)
Continuous: 10000 hours

Dimensions: Height:42 mm
Width:148 mm
Length:203 mm
Front-loader extends 138 mm

Front panel: Headphone jack
Headphone volume control
Busy LED indicator

Features: Half Height Form Factor
Mitsumi original "slide-top loading"
Direct bus interface (8 or 16 bits)
MSCDEX supported
Multi Media supported
Photo CD supported
Audio Playback function
Dust proof mechanism
32k ram buffer
350 msec average access time
Error correction with erasure function (?)
---------------------------------------------------------------------------
The CRMC-LU002S has identical specifications to the LU005S except:

Buffer size: 2352 Bytes
Access time: 1/3 stroke = 650 msec, full stroke = 1.2 seconds

The features of the LU002S are the same as the LU005S except:

The interface is 8 bits
It does not say that it supports photo cd
It does not have a large internal ram buffer

The CRS-UF series seems to be an external version of the CRMC-LU002S
(it has the same specs). The external drive is 82 mm heigh, 162 mm wide,
and 298 mm long, and the front loader extends 133 mm. It has the same
features as the LU002S.
------------------------------------------------------------------------------
The fax does not mention the CRMC-FR or the CRS-XP series drives,
(they are probably discontinued) but Computer Shopper does.

In their Feb/93 edition, CS does a review of thousands of CD-ROM drives,
half of which are probably discontinued or are only available in
Upper Volta. Anyways, the CRMC-FR is listed as internal full height (!!)

Although the model number is not mentioned, it seems that USA FLEX
is selling the LU005S for $199. I would guess that the rock-bottom
price is around $175. I've heard that the LU005S is on national
back-order; is this true?

Anyways, enjoy the info...
-Later:Wayne-
Click to expand...
 
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