JVC MSX MIDI Interface

Ascended (10821)

29-10-2015, 22:23

I bought a rare MIDI interface on eBay recently, the JVC MSX MIDI Interface. It’s from 1986 so not related to the later MSX-MIDI standard. It consists of a cartridge linked with a flatcable to a separate unit with one MIDI IN port, two MIDI OUT ports and a DIN Clock/Start/Stop port. Pretty nice!

Information about it is really scarce, but it seems like it came bundled with a piece of software called MIDI Studio Performer. (If anyone has a copy of this, please send it to me!)

I found one article in MSX-Computing’s summer 1986 edition (page 36) which describes it, quote:

“Mike Beecher of EMR paid a quick visit to be disappointed with JVC’s low profile UK marketing of his eight polyphonic track real time £170 Midi Studio Performer (digital recorder) software and interface. This is an advanced conversion from a similar package already available on Commodore, BBC, Sinclair Spectrum and Amstrad. It features full MIDI IN/OUT for touch sensitive keyboards and rhythm units plus track merging, arranging, punch-in facilities and up to 23,000 note capacity. Further modules in the suite (EDITOR, NOTATOR, etc.) will soon be available for MSX.”

Aangemeld of registreer om reacties te plaatsen

Van Grauw

Ascended (10821)

29-10-2015, 22:31

More pictures (~4MB each):

Box
MIDI interface
MIDI interface (2)
Cartridge front
Cartridge back
Cartridge pins front
Cartridge pins back
MIDI unit top
MIDI unit bottom
MIDI unit connections

I also opened up the attached MIDI unit and took some pictures of the insides:

MIDI unit board front
MIDI unit board top
MIDI unit board left
MIDI unit board right
MIDI unit board bottom

p.s. If you ever get one of these and want to open it, don’t touch the screws at the bottom, they just detach the board and you’ll end up with loose nuts inside the still-closed unit. In stead carefully pull out the plastic plugs on the sides with your fingernails (first a pin, then a plug).

I didn’t open the cartridge because I don’t think I can do it without damaging the label.

Van Grauw

Ascended (10821)

29-10-2015, 22:41

Some of my findings:

The box says “Manufactured in the UK by Electromusic Research”.
The cartridge casing has “Micro Technology-Holland” embossed on it. (It’s the same as MT-DEBUG, so I guess MT provided the casing.)
The MIDI unit’s board says “MIDI V2 © ELECTROMUSIC Research”
They labels have been filed off the ICs, but there’s a nice crystal so the UART is in the box, not the cartridge.
If I insert the interface in my turboR and CX5MII, they start running 2x as slow. (It generates IRQs periodically?)
SAVEROM.COM says there’s no ROM present in the cartridge.
Pins on the cartridge’s edge connector: /INT, /IORQ, /WR, A0-A2, A4-A7, D0-D7, GND, CLOCK, +5V, SW1, SW2. This confirms that it is I/O based. Also A3 is missing so it probably uses 8 I/O ports, and another 8 mirrored. /RD is missing but maybe it infers it from the absence of /WR?
I read all I/O ports from Basic on my CX5MII with and without this cartridge, and I did not see any differences.

If anyone knows more about this interface, has software for it or can glean some technical information from the pictures, I’d love to hear your input!

Van mars2000you

Enlighted (6563)

29-10-2015, 22:45

The software is described in MSX COMPUTING - OCT-NOV 1985 (pages 38 to 41)

http://documents.mx/documents/msx-computing-oct-nov-1985.html

Van Grauw

Ascended (10821)

29-10-2015, 23:12

Mars, lovely find, I see OUT instructions to I/O port 3. Now I know the I/O port range… Not much more unfortunately. They end the article by saying there might be a possible follow-up in 1986…

Van enribar

Paragon (1224)