MSX Interface

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By Grauw

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13-08-2017, 00:52

MSX Datapack Table 2.2 System Control Port Allocation

“ It is a bit for MSX INTERFACE. If port 0C8H is other than 0FFH, it is judged that MSX INTERFACE exists. MSX INTERFACE is a general-purpose communication LSI, but it is not currently used. ”

Looks like it never came to exist. Maybe someday we’ll be lucky and find a prototype on Yahoo auctions?

By sd_snatcher

Prophet (2566)

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13-08-2017, 03:07

At least the J3125 chip seems to have existed. It was listed on the ASCII LSI Catalog:

Google translator tells me it reads:

Quote:

J3125
MSX-INTERFACE

Asynchronous serial communication interface, frequency division circuit for generating communication interface, interface with magnetic tape, transmission. Integrated functions such as reception large capacity data buffer timer.

By Grauw

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13-08-2017, 04:10

See previous page Smile. Speculation is it is the YM3802 (MCS).

The YM3802 MCS is used in the Yamaha’s Serial I/O Unit II (Classroom Network) modules for the Russian Yamaha YIS503II/IIIR’s.

By maxis

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14-08-2017, 01:46

Grauw wrote:

See previous page :). Speculation is it is the YM3802 (MCS).

The YM3802 MCS is used in the Yamaha’s Serial I/O Unit II (Classroom Network) modules for the Russian Yamaha YIS503II/IIIR’s.

IMHO, YM3802/YM3523 is a failed to enter the mass market high performance MIDI controller for Z80 based systems. Yamaha at some point pushed MSX CX5M - CX7M as a all-in-one sequencing/synthesis open platform. But then there were severe performance problems (due to the inefficient coding, SW architecture) which ended it prematurely?? BTW, Roland MSQ-700 is Z80 based, 8 MIDI tracks, 2 independent MIDI buses!
So, looks like YM3802 came a little too late. Otherwise instead of Steinberg + Atari ST, we would have MSX reference ;))
Also an interesting feature of YM3802 is SAVE/LOAD To/From TAPE. Around mid 80s the most of sequencers/synthesizers were recording the settings/tracks/performance to the cassette.

By Grauw

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14-08-2017, 12:09

Some speculation;

Yamaha made a lot of custom chips for the MSX for ASCII like MSX-Video, MSX-Engine, MSX-Audio, MSX-Interface, and the V9978 which later became the V9990. But I think for some reason MSX-Interface failed to get picked up as a standard component by manufacturers, maybe got replaced by MSX-RS232C using cheaper components just like MSX-Audio got “replaced” by the cheaper and more popular MSX-Music.

So like the V9990 (which was too late) they tried to sell it as a standalone component to recover some of the production cost, and at least use it in their own Serial I/O Unit II for the Russian market.

By maxis

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14-08-2017, 22:48

Just as IMHO, I don't think that YM3802 is linked to ASCII. Why? It seems like ASCII always had some sort of exclusivity for the use of their chips. However, YM3802 is wide spread! Most importantly it is in music instruments. Yamaha QX5, X68000, Tandy multimedia PC etc!

By Grauw

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14-08-2017, 23:05

I see, ok, there goes my speculation Smile.

By sd_snatcher

Prophet (2566)

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15-08-2017, 00:06

maxis wrote:

It seems like ASCII always had some sort of exclusivity for the use of their chips.

I beg to disagree.

Y8950: Used in arcades, and even in a PC-98 sound card
V9938: Used in arcades, a lot of embedded Japanese hardware and even the Geneve 9640 expansion for the TI/99
V9958: Used in arcades and in many video editing equipment that were not MSX-based
S3527, S1985: Used in Japanese appliances

By maxis

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15-08-2017, 19:53

sd_snatcher wrote:
maxis wrote:

It seems like ASCII always had some sort of exclusivity for the use of their chips.

I beg to disagree.

Y8950: Used in arcades, and even in a PC-98 sound card
V9938: Used in arcades, a lot of embedded Japanese hardware and even the Geneve 9640 expansion for the TI/99
V9958: Used in arcades and in many video editing equipment that were not MSX-based
S3527, S1985: Used in Japanese appliances

I see, but I've ment high volume products. Musical instruments were sold in hundreds of thousands (big bulk). Hence, it could be difficult for exclusivity. IMHO, Y8950 is a special beast, since it could be the result of the cross licensing between ASCII and Yamaha. ASCII had no idea about the FM synthesis and/or ADPCM compression...
Also ASCII usually uses a signle letter designation "V" for video, "S" for system, etc... YM3802 is a classic YAMAHA. That's my IMHO. Also the fact is that this chip is expensive to manufacture (die size). It has built-in register type FIFOs and lot's of gates....

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