Yamaha SFG-05 for Cx5me

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By grit

Resident (53)

grit's picture

07-09-2013, 23:48

The SFG01's software is just very simple... The SFG05 software not only has disk drive support but also MIDI but it's still limited.
And - It's just the software. By using programs like MIDISlav you can make much better use of the SFG01/SFG05 FM-chip via MIDI and don't need to burn an EPROM and solder in extra address lines.

But.. if you'd like to indulge yourself:

SFG01:
http://www.cx5m.net/circuit1.htm
SFG05:
http://www.cx5m.net/circuit5.htm

Notice the address lines on IC104

By Alexey

Guardian (2340)

Alexey's picture

07-03-2016, 16:36

Btw, the schematics of SFG-05 has an error - pin 27 is connected to both A14 line and +5V. Looks like some lazy @ss copied the schematics from 01 to draw 05, but forgot to remove the +5V connection from pin 27. Also M1 signal is for some reason is called ML at pin 5 of the IC107.

By looking at the SFG-01 board I also figured that the INT signal from YM2151 was originally connected to RESET signal of YM2148 chip. So they cut that line to YM2148's pin 38 (RESET) and put a wire to pin 37 (INT). Looks like the factory's modification to me.

By Alexey

Guardian (2340)

Alexey's picture

08-03-2016, 01:53

I managed to fix the broken SFG-01 module and created 2 options for it - a ROM with original SFG-01 firmware and a slightly modified ROM with SFG-05 firmware. The A14 address line is connected from pin 27 of EPROM to pin 35 of MSX slot.

In both cases BIOSes work properly, however when using MXP2 player and MXDRV the player hangs with 05 firmware. With 01 firmware it works properly. VgmPlay works with both ROMs. I wonder whether some other changes are required for 01 module to work properly with 05 BIOS...

If someone did this conversion, please share your experience, thanks.

By Grauw

Ascended (8366)

Grauw's picture

08-03-2016, 10:40

Just the extra address line I thought, judging by the schematics. My SFG-01 was upgraded to 05 by a previous owner, looks like a little more, maybe there’s some clues for you on the picture.

By Alexey

Guardian (2340)

Alexey's picture

08-03-2016, 14:57

WOW! Looks like they could not get 27c256, so used 2x 27c128 + logic. Bulky, but works. I don't see any differences. Can you try one software for me and tell me if this works for you, Laurens? I will send it by e-mail.

By Jipe

Paragon (1366)

Jipe's picture

08-03-2016, 16:53

the mini-board with 2x27c128 is an original board of Yamaha on SFG-01

By Grauw

Ascended (8366)

Grauw's picture

09-03-2016, 19:41

Alexey wrote:

WOW! Looks like they could not get 27c256, so used 2x 27c128 + logic. Bulky, but works. I don't see any differences. Can you try one software for me and tell me if this works for you, Laurens? I will send it by e-mail.

Hey Alexey, I just tried it, it works fine here with the upgraded SFG-01! Using turboR with DOS 2 and SFG-01 in slot 2-3. Nice song btw Smile.

By Alexey

Guardian (2340)

Alexey's picture

10-03-2016, 12:24

Thanks, Laurens. We suspect that the lack of M1 signal on the FMPAC board (M1 connected to F4 circuit) could be the problem. I will verify this once I get new boards.

By Alexey

Guardian (2340)

Alexey's picture

11-03-2016, 23:52

Actually the module doesn't work with this player in other computers when 05 bios is installed. So this is not M1 related. With 01 bios it works just fine. I am out of ideas...

By Alexey

Guardian (2340)

Alexey's picture

13-03-2016, 17:16

I tried to upgrade my second SFG-01 module to 05 with the same BIOS and 27c256 EPROM. Still the same problem - player hangs. So this could be BIOS incompatibility with the older board or the problem with the BIOS itself. Could someone send me the 05 BIOS that really works with his upgraded 01 module? Even if it is splitted into low/high bytes.

Has anyone actually successfully upgraded his module himself? If yes, please send me your BIOS, thanks. Laurens?

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