I installed a V9958 in my msx2 Hb-F9s, and works but...

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By Dhampird

Hero (585)

Dhampird의 아바타

17-06-2010, 04:18

Hello i finished the install of a vdp V9958 in my msx2 HB-F9s, and i see boot msx and the image ok, but i tried to run the game F1 Spirit 3D fro MSX2+ and dont run, then, what i need to test the v9958 or to run msx2+ games in my msx2 with V9958, i need to know if is possible to test and if is normal that not run msx2+ game.

Thanks a lot.

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By lovemsx

Resident (41)

lovemsx의 아바타

17-06-2010, 04:32

It's necessary burn a new bios msx2+

good luck
Wink

By Dhampird

Hero (585)

Dhampird의 아바타

17-06-2010, 04:37

Ok, thanks for reply, the problem is that my system is msx2 hb-f9s Spanish, i dont know how to modify the .rom files to can burn the .rom in willem, i think there is 3 .rom files for the msx2+, i will need put all three? how?

Thanks a lot.

By Retrofan

Paragon (1214)

Retrofan의 아바타

17-06-2010, 13:17

Hello i finished the install of a vdp V9958 in my msx2 HB-F9s, and i see boot msx and the image ok, but i tried to run the game F1 Spirit 3D fro MSX2+ and dont run, then, what i need to test the v9958 or to run msx2+ games in my msx2 with V9958, i need to know if is possible to test and if is normal that not run msx2+ game.

Thanks a lot. Try this: insert DOS2 cartridge (when computer is offline!) and then enter in Basic: "Call System" with the F1 Spirit 3D floppy in the diskdrive. Maybe I'm wrong, but I thought I read this trick in the '90s. If you don't have DOS2 cartridge, use MegaFlashROM SCC cartridge instead with flashing the DOS2 rom in it.

By RetroTechie

Paragon (1563)

RetroTechie의 아바타

17-06-2010, 14:04

Nice to hear that V9958 works... Smile

Dhampird & me had some e-mail exchange, amongst others about that diode from V9958 to Z80 #WAIT input. I know what it does physically speaking (allow the V9958 to put the Z80 'on hold' for some clockcycles), but is it needed? And what for, exactly? Does anyone know of some easy way (software) to test/show the effect of that diode present/missing (or reversed) ?

I feel kind of silly for asking, but even hardware modder's memory gets blurred sometime... Murdoch also it isn't obvious since V9938 and V9958 are very similar timing-wise (so V9958 needing this, doesn't make sense when V9938 works without it).

By muffie

Paladin (933)

muffie의 아바타

17-06-2010, 15:12

He'll need a rom without that LATCH F4 thing isn't it?
AFAIK it's just changing a byte! somewhere.

By NYYRIKKI

Enlighted (5396)

NYYRIKKI의 아바타

17-06-2010, 15:47

To boot MSX2+ you need 3 ROMs: main ROM, EXT ROM and Kanji BASIC ROM. (Kanji BASIC ROM slotID is hardcoded and need to be changed according to setup)
How ever the Kanji BASIC ROM is only needed for boot logo and extended kanji commands, that are both quite useless. By removing boot logo call the system boots up normally. You need to consider if building 3rd ROM is worth the trouble.

muffie also mentioned F4 latch, but I have not managed to find any use for it while testing ROM sets in emulators... but maybe that is because I have patched the ROM to skip boot logo anyway... Somebody correct me if I'm wrong.

I've also made an IPS patch to convert MSX2 main ROM to MSX2+ main ROM without touching localization settings (like font or keyboard). Mail me if you are interested. The EXT ROM needs manual patching if you still want to boot the computer to 50Hz mode...

... and last tip: It is always good idea to run test round on OpenMSX or BlueMSX before burning actual ROM's.

By Dhampird

Hero (585)

Dhampird의 아바타

17-06-2010, 17:14

Hello again everyones, first of all i have to give thanks greatly for the fully help and patience to "usuario_msx2" and "RetroTechie", without your help i will cant do the mod. Thanks again.

I make some photos after installation, you could see below, dont show the V9958 with the Heatsink for the moment,i put a provisional aluminium heatsink from pc, now i´m seeking for an original msx heatsink for V9958 to fits exactly in my HB-F9s, if anyone have ones of this please tell me (dumpil@gmail.com)

About run F1-Spirit 3D for MSX2+ i think the only way is changing the BIOS in my MSX2 for another BIOS for MSX2+ prepared for my system HB-f9s, i dont so much about this, how to prepare or edit the .roms PLUSBIOS.ROM, PLUSDISK.ROM, PLUSSUB2.ROM to will be compatible with my system HB-F9s with Spanish Keyboard and if i will need burn each file in one eprom or i could use only 2 eproms for the job, in an e-mail exchange with "RetroTechie" (thanks again for the instructions and fully info) explains me that probably the best way will be use 27C256 + 27C512 combo eproms and ~120 ns. or faster for Turbo updates.

To "NYYRIKKI" i will mail you early, thanks for reply.

I´ll interested to do much mods in my HB-F9s, step by step, for the moment the important thing is change the BIOS, and when it is finished i will possibly try the F4 Register if i can. Anyways, i think that this post will be correct if we talk only about
the V9958 and its associated mods, mix another mods in this post will be confused, for example i saw an article from Hans0 that explains how to fix "contamination voltage from power supply and avoid V9958 problems" in V9958, i think is interesting because this circuit could protect the V9958, the problem is that when we replace the V9938 by V9958 we need to do some wirings to adapt the vdp to MSX2, this wires would be in cortocircuit if we do the Hans0 diagram, because the GND and +5V joins, i need to find another way to makes this circuit works on a MSX2 with the vdp9958 adapted, will be great find a way, i read from people that tells its V9958 in MSX2 had a lot of problems in screen with colors and
other problems, i wonder if this circuit could fix their problems. I post the original diagram from Hans0 ,and a diagram show the cortocircuit points if we do the mod with a V9958 adapted to MSX2, will be possible complete circuit another way?

*V9938 to V9958 in MSX2 HB-F9S*

img820.imageshack.us/img820/3505/v9958wirings1.jpg

*V9958 placed in Socket in MSX2 HB-F9S*

img293.imageshack.us/img293/4407/vdp9958socket1.jpg

*Hans0 Diagram to Fix Contamination Voltage in V9958*

img51.imageshack.us/img51/2420/fixcontaminationfrompow.jpg

*Hans0 Diagram to Fix Contamination Voltage in V9958 combined with V9938 to V9958 in MSX2*

img707.imageshack.us/img707/2420/fixcontaminationfrompow.jpg

Thanks again for help.

By RetroTechie

Paragon (1563)

RetroTechie의 아바타

17-06-2010, 18:05

muffie also mentioned F4 latch, but I have not managed to find any use for it while testing ROM sets in emulators...
MSX2+ hardware reset includes destructive RAM test which makes sure that some badly cracked ROMs don't restart after a reset. Maybe an emulator erases memory anyway if you tell it to reset the machine, but that's not how real-world MSX'es behave. If a ROM hangs there, you'd need power off/wait some time/power on. Do that too quick, and you have to repeat it. Crazy So most users would want that memory counter (also nice if you plug in an external mapper, and immediately see that it's detected).

MSX2+ uses that F4 latch to enable 2nd kind of reset, equivalent of software jump to ROM address 0 (for MSX2 this is same as hard reset). Cuts the restart time a little, but you have to (be able to) enter relevant command. IMO that's something you can easily do without, eg. by patching ROMs to ignore F4 latch and always do hard reset.

I don't see why you'd want to skip those boot logo / Kanji ROMs. In some models (Philips 8235 / 8245 comes to mind), it may be difficult to fit the added ROMs together with existing one. In which case cutting out those extra ROMs may be preferred. But in the HB-F9P/S, you could replace subROM with a 64K EPROM just as easily as with a 16K or 32K EPROM. Afaik you don't have to adapt those Kanji ROMs, so you don't save any effort by cutting them out. Include them, and those Japanese screen mode(s?) work like on real 2+. And: after all the effort to build 2+ from MSX2, don't you want to see that 2+ logo?

Read: leave out F4 latch it you don't mind losing the 'software reset' option. Cut out the extra 32K ROMs if it's difficult to fit them in a machine, or when you really don't want to wait for that 2+ logo to show.

So: does anyone have a full MSX2+ ROM set adapted to Spanish keyboard layout / european settings? Or knows where to find them? I'd guess 2+ ROMs used for HB-F700S would be fine too (with diskROM removed).

By RetroTechie

Paragon (1563)

RetroTechie의 아바타

17-06-2010, 18:56

You've got pin 4 wired to GND (thick red wire = GND oO ), while schematic shows 100K resistor to +5V (resistor is bullshit btw., since V9958 pin 4 is an input, no need for current-limiting). Perhaps you just need a fixed logic level, I can't tell from the datasheet since it doesn't explain clearly what purpose those #HRESET / #VRESET signals serve). If you don't see any weird behaviour, I guess you can leave that as is.

Beside that this diode to Z80 #WAIT input, and VDD-DAC (+5V) supply filter is missing, it looks okay to me... all a +5V filter on VDD-DAC (pin 21) would do, is improve stability / quality / 'crispness' of the image output. So watch for image disturbances etc. to judge if such a filter is needed.

Btw.: if anyone in the Netherlands (read: cheap shipping for me) has such a ceramic V9958, and is willing to swap it for a NOS (New Old Stock = old, but unused) plastic one, drop me a mail... I've got 4 of those V9958's (all plastic), and wouldn't mind having a ceramic version as well. Maybe you don't care either way, and would rather have plastic, unused / 'new' V9958 than ceramic, but old / used one? Shipping costs would be on me, of course.

dont show the V9958 with the Heatsink for the moment,i put a provisional aluminium heatsink from pc, now i´m seeking for an original msx heatsink for V9958 to fits exactly in my HB-F9s, if anyone have ones of this please tell me
Just forget that heatsink - ceramic V9958 doesn't need it, all it would serve to do is create a short circuit if it ever comes loose.

By Dhampird

Hero (585)

Dhampird의 아바타

17-06-2010, 21:20

Hi again, about the MSX2+ boot logo i´m agree with you "RetroTechie", i think will be better keep this, dont skip. Also will be great to know how modify "the memory counter" (piece of code) to can show in boot up the 512K RAM installed on my HB-F9s, i mailed to Bas kornalijnslijper about his "memory counter part" but he told that is for MSX Philips. Then the only way to do this is that anyone expert tell me how to modify to show up 512K. Anyone in this forum can help with it?

I´m glad to know that the ceramic V9958 dont need heatsink, another thing that i dont have to do, locate MSX V9958 heatsink (difficult but i had in mind) and buy some termal adesive paste to install on V9958.

Then i will need to step forward:
Anyone have a full MSX2+ ROM set adapted to Spanish keyboard layout / european settings? Or knows where to find them? I'd guess 2+ ROMs used for HB-F700S would be fine too (with diskROM removed).Will be great that someone had information about to locate the way to show up in boot the memory of 512K, change any line of the .rom code?how?

Thanks a lot RetroTechie and all of people that can helps.

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