Future Project MSX2+ HB-F1 XV Msx Super Turbo...

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By Dhampird

Hero (585)

Dhampird's picture

21-09-2016, 17:22

Probably i could get another more XV, if i get another i could prepare it with the same mods like the XV on the video to someone in the forum:
MSX2+ HB-F1 XV + 512K SRAM internal + Update Bios + Z80 10Mhz or 8Mhz + Msx Super Turbo 8Mhz + All Electrolitic caps changed to New ones.
If anyone is interested let me know, or if you want modify your XV also and you are not pretty sure to try it.
I dont know yet prices, i have to get materials and calculate all parts, time and work.

By Protoman

Resident (44)

Protoman's picture

22-10-2016, 14:15

Very nice example! Smile I also upgraded my F1-XV with the 512K SRAM upgrade and it works very well! Big smile Which model of Z80 processor do you recommend for making a turbo circuit modification? So far, I've only found the Dutch circuit schematic for the Turbo 7Mhz upgrade by Digital KC...

By usuario_msx2

Paladin (755)

usuario_msx2's picture

12-11-2016, 18:46

@Meits
Try konami's twinbee ☺

By Manuel

Ascended (18082)

Manuel's picture

12-11-2016, 20:46

I wonder why the sound is still OK with this upgrade indeed. Did you make sure the PSG gets a different clock than the Z80 or something?

By Protoman

Resident (44)

Protoman's picture

13-11-2016, 10:37

Hello! Yes, I've been trying to figure out how to fix the PSG and internal FM sound on this same model HB-F1XV with the 7Mhz turbo installed, but I'm having a lot of trouble :/ I also upgraded the memory to 512K SRAM (I followed the SRAM guide from Tabajara Labs) and I have SRAM pin 22 (/CE) wired to the S1985 pin 53 (/SLT3-3.0). Here's what I tried so far:

Test 1) Installed a Z84C0010PEC Z80 10Mhz with the 7Mhz turbo circuit, but I'm having the blank screen/ freezing issue when switching the turbo on after wiring the VDP 3.58Mhz CLK signal directly to pin 30 of the S1985, after lifting the pin from the board trace.

Test 2) With the VDP CLK signal still going to pin 30 of the S1985, I tried swapping the SRAM pin 22 (/CE) from S1985 pin 53 (/SLT3-3.0) to pin 56 (/SLT33), according to user "Colemu" who appears to have fixed the PSG audio issue with his HB-F1XD MSX2. 7MHz MSX Upgrade - Trouble Shooting.

Quote:

At first this didn't work, but I remembered that my SRAM was wired up to CAS. I figured it wouldn't work in DRAM config, do wired my memory up to SLT33. It worked like a dream!

Test 3) I replaced the S1985 CLK signal to the 7Mhz turbo CLK signal, which allows the computer to function correctly at 3.58Mhz and 7Mhz speeds (with distorted PSG and FM sound). I then removed pin 8 (CLK) of the YM2413 from the 7Mhz CLK signal of the turbo board, and connected the YM2413 pin 8 to the VDP pin pin (3.58Mhz CLK). Here is where things get really strange!

At first, I tested a converted PSG to FM sound game "Ys" using the NandemoFM conversion from user "Tiny Yarou". The FM sound worked perfectly with the turbo enabled at 7Mhz! However, the PSG sound effects were still distorted (of course). BUT, when I tried various commercial games released with FM sound, like "Laydock 2 - Last Attack" and "Ashguine 2", the FM sound is not detected and the games play in only PSG audio. So even when running at 3.58Mhz non turbo mode, with the YM2413 connected SEPARATELY to the VDP 3.58MHz CLK signal, these commercial games DO NOT DETECT the internal FM sound chip! oO If I plug in an FM PAC to an external slot, the FM sound works, although the turbo causes distorted sound on the FM as well as PSG effects. When it comes to the "Ys" test using FM sound, the FM PAC causes the sound to become distorted (and lower volume level) when I enable turbo mode, and the audio level becomes louder as though the FM PAC signal is taking over instead of the internal FM sound.

Any ideas whey the Tiny Yarou coded FM conversion works correctly on the 3.58Mhz separate CLK signal, but real FM games don't detect this? I'm REALLY struggling to figure out how to make turbo enabled sound function correctly, because I know it's possible with at least two of the MSX.org users machines! :o

By Louthrax

Prophet (2406)

Louthrax's picture

13-11-2016, 11:27

It might be that Tiny Yarou is using timers to access the FM-PAC ports. Most of the games are just using Z80 loops to delay accesses to the VDP ports: this works only if your CPU is at "normal" speed. The other option is to use a real timer to always have the same delay, but this high-accuracy timer is turboR specific and does not exist on normal MSX2.

EDIT: Maybe Tiny Yarou just detects the Turbo mode and adjusts its waiting loops accordingly.

By Protoman

Resident (44)

Protoman's picture

13-11-2016, 12:38

Hmmm, interesting! I was thinking there was something with the timing involved with the FM! Shocked! I still wonder why the MSX2 / MSX2+ with S-1985 PSG turbo audio fix still doesn't seem to be well-known or documented. I would think there would be many users with turbo that would be interested in fixing the PSG audio of their MSX2 / MSX2+ machines. Question

I actually found a different diagram showing a 512K SRAM memory chip wired to an S-1985 from the HBF1-XV which shows DIFFERENT wiring to the /OE and /WE pins of the SRAM. HBF1-XV SRAM Japanese

With the Tabajara Labs information, the SRAM pin 24 (/OE) is wired to the Z80 pin 21 (/WR) and SRAM pin 29 (/WE) is wired to the Z80 pin 22 (/RD). However, that Japanese site shows the SRAM pin 24 (/OE) wired to the DRAM socket pin 1 (/OE) and the SRAM pin 29 (/WE) wired to the DRAM socket pin 4 (/W). Is this the so-called "CAS mode"? I thought SRAM can't be wired as DRAM with CAS strobe signals...?

By Protoman

Resident (44)

Protoman's picture

13-11-2016, 15:49

Okay, new test update!

Test 4) Remove SRAM pins 24 and 29 and connect to the DRAM socket pins 1 and 4. This causes the machine to NOT BOOT at all. So it appears that I indeed have the SRAM chip wired correctly when pins 24 and 29 go to the Z80 pins 21 and 22.

Test 5) I removed the Turbo 7Mhz diode interrupt signal from the Z80 pin 20 (IO RQ) and tested running "Vampire Killer" with turbo enabled. This results in corrupted graphics across the screen as seen in my video link. BUT, the PSG sound DOES NOT appear to be distorted! HB-F1XV Turbo without IO RQ test

How is it possible to get the system to boot with PSG at 3.58Mhz and turbo enabled?? :o

By Dhampird

Hero (585)

Dhampird's picture

04-12-2016, 14:22

Hello everyone,

Quote:

I wonder why the sound is still OK with this upgrade indeed. Did you make sure the PSG gets a different clock than the Z80 or something?

The S1985 is still working at 3.58Mhz meanwhile Turbo in ON (8Mhz), then PSG is working at 3.58Mhz (sound ok) meanwhile Turbo is ON
Also tell that internal FMPAC sounds ok meanwhile Msx Super Turbo is ON (8Mhz).

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