The Big MegaFlashROM SCC+ SD Topic | MSX Resource Center (Página 64/96)

Hero (534)

07-01-2016, 23:28

The only reason to worry about sending OPN FM writes to the PSG port if a PSG is connected is that the PSG only acknowledge register values 0-15 and OPN acknowledges all 8 bits (256 registers) so writes to OPN registers higher than 15 would end on PSG registers, causing it to produce weird noise. If you only send PSG commands both chips will produce only PSG sound even if both are connected together on the same port.

@Guillian: There are two PSGs inside the MegaFlashrom SCC+ SD? One at port 10h and one at A0h, right?

Does it obey MSX standard of mirroring within 8 addresses (ASCII/Yamaha stuff) or it is like Toshiba stuff (only at the first I/O port)?

On most MSX computers you can access the PSG on all addresses from A0h to A7h. On the ones using Toshiba engines you can only access the PSG at port A0h.

Por Grauw

Ascended (10819)

07-01-2016, 23:48

@Guillian: Ok, thanks!

@l_oliveira: There’s one PSG which can optionally be mirrored to A0H-A2H on the SCC+ SD. The non-SD version does not have this mirroring feature.

I just tested, the PSG register selection of the MegaFlashROM SCC+ SD is mirrored every 10H just like the real PSG, so it may not be a good idea to put the OPN there as well… maybe 14H-16H is a better location.

Por Grauw

Ascended (10819)

08-01-2016, 00:08

Guillian wrote:

Both PSGs are write only.

The best way to check for the presence of a MFR SCC+ (SD) is to: [...]

Ok, thanks for the info!

l_oliveira wrote:

There are two PSGs inside the MegaFlashrom SCC+ SD? One at port 10h and one at A0h, right?

There’s one PSG which can optionally be mirrored to A0H-A2H on the SCC+ SD. The non-SD version does not have this mirroring feature.

l_oliveira wrote:

The only reason to worry about sending OPN FM writes to the PSG port if a PSG is connected is that the PSG only acknowledge register values 0-15 and OPN acknowledges all 8 bits (256 registers) so writes to OPN registers higher than 15 would end on PSG registers, causing it to produce weird noise. If you only send PSG commands both chips will produce only PSG sound even if both are connected together on the same port.

I just tested, the PSG register selection of the MegaFlashROM SCC+ SD is mirrored every 10H just like the real PSG, so it may not be a good idea to put the OPN there as well… I think 14H-17H is a better location for OPN / OPNA. Would also allow playback of triple-PSG VGMs.

Por Bondy

Resident (54)

13-01-2016, 00:41

Hi, Is it not possible to save in Snatcher SD via a flashed (the newer way) floppy with the megaflashrom SCC+ SD?

Por Guillian

Prophet (3528)

13-01-2016, 09:06

Bondy wrote:

Hi, Is it not possible to save in Snatcher SD via a flashed (the newer way) floppy with the megaflashrom SCC+ SD?

Yes, it is possible to save into DSKs using the newer way.

Por mfeingol

Champion (294)

13-01-2016, 21:50

@Guillian:

I was wondering if you might able to take a look at these roms, and figure out why they seem to work with openmsx when inserted as a "real" cartridge, but when flashing with an mfrscc+sd and opfxsd: http://1drv.ms/1ZuZ87C

E.g. with madmix2.rom, the game will boot to the splash screen, but then it hangs. With openmsx and madmix2.rom inserted in slot 1, pressing space at the splash screen leads to the game.

I've tried changing the rom types and flashing with /u, but I wasn't able to find a combination that worked.

Thanks!

Por Manuel

Ascended (19676)

13-01-2016, 22:15

krakout and huphrey are using ASCII16kB and the other 2 ASCII8kB mappers. Did you try to specify these mapper types in opfxsd?

Por Manuel

Ascended (19676)

13-01-2016, 22:16

Btw - Never played this Humphrey game before. It's pretty good!

Por mfeingol

Champion (294)

13-01-2016, 23:19

My apologies for the imprecise bug report.

Testing using openMSX cart slot 1 and opfxsd 1.14 on an A1ST.

Abu Simbel auto-detects as ASCII8 with opfxsd. It works in openMSX, but hangs after the splash screen when flashed with opfxsd.

Mad Mix 2 auto-detects as ASCII8 with opfxsd. It works in openMSX, but hangs after the splash screen when flashed with opfxsd.

Krakout auto-detects as ASCII16 with opfxsd. It works in openMSX's slot 1. It works with opfxsd. However, Sofarun hangs in "Saving Sofarun settings..." when launching it. An issue for @louthrax, I guess.

Humphrey auto-detects as ASCII16 with opfxsd. It works in openMSX's slot 1. It works with opfxsd. However, Sofarun resets when launching it. Another one for @louthrax.

And yeah, Humphrey is a really good game, despite its Spectrum origins.

Por Bastiaan

Champion (333)

14-01-2016, 12:24

what humprey game/ version do you mean? I don't think I ever played it either...

http://www.generation-msx.nl/software/result?q=Humphrey&sear...

ascii16 mapper for a tape game?