MiSTer FPGA Forum

Hi, I'm having a heck of a time getting Space Quest to run in Tandy mode on the pcxt core.

In the pcxt mode with pcxt31.rom, I can load up my ao486 vhd to access the game directory. The colors are not correct in CGA (they show up as orange, green, etc.) My original cga xt computer I had it was cyan, pink, white etc etc.

In SQ1 there is a option in the menu to change the video mode. This switches from black and white to the 4 colors. When I run it in monochrome there are gaps between the columns of pixels that I don't remember seeing on original hardware. I can only get it to close to correct if I turn on composite video mode but then its more than 4 colors and very blurry.

Every time I run the game it plays the sound in international speaker mode with a single voice.

My goal after learning that tandy sound has 3 voices and is better than the international speaker I grew up with, was to get these old sierra games running in tandy mode.

So I created the bios files for tandy using the python scripts.

When I switch the core to tandy mode, It can no longer see my hard drive vhd and will only boot off a floppy img of the tandy1000 dos 2.1 disk.

I have a real 486 pc with a real floppy drive. I then took my original floppies for space quest (dos/tandy) and Xcopyied the files to my system drive (compact flash). I then used winimage to create 360kb disk images to .ima files which I renamed to .img

After that I can load up the sq1 disk img into the mister in tandy mode, after booting dos 2.1, and the core can read the disk.
I tried to run the sierra.com and it then asks me to insert the ORIGINAL disk in the A drive....

I also noticed that if I'm in tandy mode, and try and run a 1.44mb floppy img of dos6.22 it seems to start to read it but then just freezes. I assume the tandy can only read 360kb floppies?

I gave up at this point.

Update:
I got it working. I added the ide_xtl to the ec00 bios and then I was able to run in tandy mode with vhd support.

When I ran sq this way I am now getting the correct sound. I'll leave this post up just in case it helps someone else, and perhaps there's a way to switch the cga color pallet for the pcxt mode?

Most of your problems with running games are described in the wiki (need for XTIDE bios, only 360kb images for Tandy).

Regarding the colours, I think Space Quest on Tandy uses EGA-like graphics, so they might be different. EDIT: I see now you're talking about pcxt mode, so scratch that.

If you're interested in games with Tandy-exclusive fx you can check my collection.

akeley wrote: ↑Sun Dec 10, 2023 9:17 am

Most of your problems with running games are described in the wiki (need for XTIDE bios, only 360kb images for Tandy).

Regarding the colours, I think Space Quest on Tandy uses EGA-like graphics, so they might be different. EDIT: I see now you're talking about pcxt mode, so scratch that.

If you're interested in games with Tandy-exclusive fx you can check my collection.

Thank you, I tried your link to the wiki but it directs me back here to this post.

Does anyone know what video mode this core (pcxt) uses to support analogue rgb output to a pvm. In the ao486 core, everything I’ve tried via the mister ini and custom video modes to get an image either doesn’t display correct if at all. The one mode that I get an image, the dos txt is garbled.

In Tandy mode on pcxt core I also discovered after I quit space quest or sq2, the OS reports an error:

‘Dos mem corrupt, first_mcb=028e
Prev 2f54:0000:4d ….
NotMZ9bff….

PANIC: MCB chain corrupted
System halted”

On the color pallet. Is it possible to add a toggle to the core to let the user select between the cga color pallets? I’m not sure what controls which pallet. But as a kid my cga monitor had a button that toggled between the 4 color cyan and monochrome. I never could change the pallet on my original hardware.

Space Quest works fine for me on PCXT in Tandy mode.
Make sure that:

• Model is "Tandy 1000" in the System & BIOS menu

• You have a tandy bios selected in the same menu

If Tandy is setup correctly, you will see text in low res mode that says:

MEMORY SIZE = 640K

as soon as you boot (it will take longer to load the BIOS and read drives)

Zarkov wrote: ↑Sun Dec 10, 2023 9:55 pm

Thank you, I tried your link to the wiki but it directs me back here to this post.

Does anyone know what video mode this core (pcxt) uses to support analogue rgb output to a pvm. In the ao486 core, everything I’ve tried via the mister ini and custom video modes to get an image either doesn’t display correct if at all. The one mode that I get an image, the dos txt is garbled.

In Tandy mode on pcxt core I also discovered after I quit space quest or sq2, the OS reports an error:

‘Dos mem corrupt, first_mcb=028e
Prev 2f54:0000:4d ….
NotMZ9bff….

PANIC: MCB chain corrupted
System halted”

On the color pallet. Is it possible to add a toggle to the core to let the user select between the cga color pallets? I’m not sure what controls which pallet. But as a kid my cga monitor had a button that toggled between the 4 color cyan and monochrome. I never could change the pallet on my original hardware.

Sorry, the wiki link is: https://github.com/MiSTer-devel/PCXT_MiSTer

To display on a 15kHz CRT I use this modeline (you have to add this segment in Mister.ini):

[PCXT]
direct_video=0
vga_scaler=1
vsync_adjust=1
vscale_mode=3
video_mode=1280,120,140,202,240,2,0,22,27565 ; New Best Wider 06-25-2021

Otherwise the in-game image will disappear, while Norton Commander is fine. I guess it might to do with weird CGA this coure outputs.

This modeline comes from ao486 set. This core can't display on 15kHz at all without them (core outputs 31kHz). You can find them here or newer version here.

About the Space Quest colours, I guess this is a bit of a rabbit hole. Your photo is the same how it looks on my CRT set. Mobygames screenshot seems similar to me, but I never had good eye for colour, what do you think?

Unfortunately it's near impossible to find photos of games on original CGA monitor. Also, you can search Nerdly Pleasures blog ofor CGA -related articles, there are many examples of different versions, colours, and looks.

Newsdee wrote: ↑Mon Dec 11, 2023 7:44 am

Space Quest works fine for me on PCXT in Tandy mode.
Make sure that:

• Model is "Tandy 1000" in the System & BIOS menu

• You have a tandy bios selected in the same menu

If Tandy is setup correctly, you will see text in low res mode that says:

MEMORY SIZE = 640K

as soon as you boot (it will take longer to load the BIOS and read drives)

20231211_153617.JPG

Yup, Tandy mode looks correct. My pics are in pc xt cga mode.

akeley wrote: ↑Mon Dec 11, 2023 8:37 am

Zarkov wrote: ↑Sun Dec 10, 2023 9:55 pm

Thank you, I tried your link to the wiki but it directs me back here to this post.

Does anyone know what video mode this core (pcxt) uses to support analogue rgb output to a pvm. In the ao486 core, everything I’ve tried via the mister ini and custom video modes to get an image either doesn’t display correct if at all. The one mode that I get an image, the dos txt is garbled.

In Tandy mode on pcxt core I also discovered after I quit space quest or sq2, the OS reports an error:

‘Dos mem corrupt, first_mcb=028e
Prev 2f54:0000:4d ….
NotMZ9bff….

PANIC: MCB chain corrupted
System halted”

On the color pallet. Is it possible to add a toggle to the core to let the user select between the cga color pallets? I’m not sure what controls which pallet. But as a kid my cga monitor had a button that toggled between the 4 color cyan and monochrome. I never could change the pallet on my original hardware.

Sorry, the wiki link is: https://github.com/MiSTer-devel/PCXT_MiSTer

To display on a 15kHz CRT I use this modeline (you have to add this segment in Mister.ini):

Code: Select all

[PCXT]
direct_video=0
vga_scaler=1
vsync_adjust=1
vscale_mode=3
video_mode=1280,120,140,202,240,2,0,22,27565 ; New Best Wider 06-25-2021

Otherwise the in-game image will disappear, while Norton Commander is fine. I guess it might to do with weird CGA this coure outputs.

This modeline comes from ao486 set. This core can't display on 15kHz at all without them (core outputs 31kHz). You can find them here or newer version here.

About the Space Quest colours, I guess this is a bit of a rabbit hole. Your photo is the same how it looks on my CRT set. Mobygames screenshot seems similar to me, but I never had good eye for colour, what do you think?

Unfortunately it's near impossible to find photos of games on original CGA monitor. Also, you can search Nerdly Pleasures blog ofor CGA -related articles, there are many examples of different versions, colours, and looks.

The pallet my old cga system used was the blk, cyan, pink, white.

The pallet it is using is still a cga pallet but it’s just not the one my hardware used.

I agree it’s gonna be really hard to recreate it exactly but I’m very curious where those vertical column lines are coming from.

Maybe original cga monitor was a different resolution or drew the screen differently than how it’s handled on a pvm or the digital hdmi output.

My memory of it on cga the pixels didn’t have the gaps. I used to hate the cyan color so I played in b/w mode on my cga monitor. So it looked like how it looks in Ega on ao486 but with no color. The closest I can get it to this is using the composite vid on option combined with the b/w color selection in the f12 menu. This fixes the gaps.

I understand this is all a minor thing as I think most ppl will run it in Tandy mode or on the ao486 for the 16 color ega/vga.

Thx for the 15kh modes I’ll try those out.
From my understanding my pvm on analogue rgb is 15kh, and a vga monitor uses 31kh. My goal is to have every core I use run on the analogue out to the pvm.

Pallet:

Tried all the modes on the ao486 core but it refuses to output a 15kh signal.

One of the modes looks pretty great in games but dos txt is always slightly chopped off and can be hard to read.

I read the ao486 core is 31kh or hdmi only.

Makes sense as the original hardware couldn’t output to a tv either. But I’m pretty sure you could install isa cga/ega cards in 486 mb’s as they still had isa slots.

After seeing dos in the pcxt core on my pvm perfectly clear I just wish it could be possible to get the same output for ao486.

One other issue the Tandy core has an odd keyboard map and the keys I use on the numpad to move the avatar in sierra games don’t function correctly. Backspace is also mapped elsewhere.

I believe I just need to do a kb re-map in the menu. Only I think that will apply to all the modes for the pcxt core (pcxt mode works fine, only Tandy is affected). I might try binding up a usb game pad to get the full 8 directions. Maybe the core could have a selector to let you choose if you want an original Tandy kb layout or if you want a modified one that maps correctly to a standard pc kb. Also the games did support joystick but I haven’t tested if it works yet.

I’m always amazed at what the mister can do.
Thank you for everyone’s hard work.

Zarkov wrote: ↑Mon Dec 11, 2023 2:08 pm

Tried all the modes on the ao486 core but it refuses to output a 15kh signal.

One of the modes looks pretty great in games but dos txt is always slightly chopped off and can be hard to read.

If as you say "it looks great in games" then that's 15 kHz modelines working as intended. The trade off is the slightly garbled text in DOS, but there's no way around it, and it's sufficiently readable anyway for navigation purposes. You can of course use a 31kHz PC monitor, but that's a different story.

akeley wrote: ↑Mon Dec 11, 2023 2:20 pm

Zarkov wrote: ↑Mon Dec 11, 2023 2:08 pm

Tried all the modes on the ao486 core but it refuses to output a 15kh signal.

One of the modes looks pretty great in games but dos txt is always slightly chopped off and can be hard to read.

If as you say "it looks great in games" then that's 15 kHz modelines working as intended. The trade off is the slightly garbled text in DOS, but there's no way around it, and it's sufficiently readable anyway for navigation purposes. You can of course use a 31kHz PC monitor, but that's a different story.

Thing is, if I run the pcxt core the txt is not garbled. In the mister menu I can see it outputing 15kh but in ao486 I’ll see a higher kh number.

Ya I’ll be running a vga monitor for the ao486 but switch to my pvm for the pcxt and Tandy. I suppose I could also run the pcxt core on the vga as well with the scan doubler setting.

Zarkov wrote: ↑Tue Dec 12, 2023 8:11 am

Thing is, if I run the pcxt core the txt is not garbled. In the mister menu I can see it outputing 15kh but in ao486 I’ll see a higher kh number.

These are two different cores/machines. PC/XT outputs 15kHz CGA signal and ao486 dodgy 31kHz VGA. That's why you need modelines for ao486 to be able to display it on 15kHz at all. And the DOS vs in-game frequencies also differ.

I played more sq1 on Tandy mode.

I remapped some keys:
\ to num pad 7
4,8,6,2 on num pad to left, up, right, down
Num pad 7 to regular 7 key

This fixes the backspace and lets me use the num pad for all 8 directions.

But if you go back to pcxt mode the kb will be incorrect since both machines are under one core and I find resetting the remap using the clear isn’t working the way I expect and I have to manually undo them.

Using the reset settings under the system menu doesn’t reset the remaps.

Sq1 Tandy mode:
I progressed further into the game and it froze on me a few times and I needed to restart the core from the menu. When it froze the audio was also looping. This happened in the bar after exiting from the slot machine and also during the slot machine.

I changed from pc/at speed to the 7mhz speed and it seems to have helped. Also, I disabled the low tech memory setting. I’m thinking it might be due to that area of the game taxing the system more as it’s got animations and loops the band stand music. Once I walk outside, I can see the speed return to normal.

Saving and loading in the bar seemed to bog down too.

I’m going to go through the entire game so I’ll try and log other issues I run into.

Oddly I noticed that you can’t type numbers like “5” because the number keys below the function keys seem to map to directions on the Tandy and the num pad keys do the same. I could only get a “0” to work. So if I ever need to type any numbers I think I’ll need to switch to pcxt mode.

It’s too bad there’s not an option in the core menu to use a standard kb layout.

Also in pcxt mode if I turn on the num lock I noticed that the number 5 would not output when I pressed the key, where as 0-4 and 6-9 worked.

Fortunately in sq1 the part where you have enter a code has an arrow you move around with the direction keys to press numbered buttons on screen. But if I ever need to type numbers it may be an issue esp on the Tandy mode.

Lastly, I looked up the Tandy kb and it looks like it had keys for numbers and a num pad so there’s gotta be a way to make it play nice on a standard kb.