New hardware I/O board using Parallax Propeller (VGA,Sound,Joystick,etc)

Any discussions related to the creation of new hardware or software for the ZX80 or ZX81
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mrtinb
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Re: New hardware I/O board using Parallax Propeller

Post by mrtinb » Tue Jul 30, 2019 3:56 am

Have you seen the ZX81VGA page, which also creates VGA and more with a Propeller?

http://zx81vga.ws-nbg.de/main.php
Martin
ZX81, Lambda 8300, Commodore 64, Mac G4 Cube

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blittled
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Re: New hardware I/O board using Parallax Propeller

Post by blittled » Tue Jul 30, 2019 4:55 am

Bean,
It's great to see a fellow Propeller user here. I am extremely interested in your project. I just started working on a copy of Andy Rea's FPGA ZX-81 on a DE0-Nano using a Propeller Professional Development Board (PPDB) Version 1.0. For those that do not know of the PPDB you can find info at https://www.parallax.com/product/32111. It has a Propeller and a lot of nice peripherals such as VGA, Composite, PS2, RS232 and more. So once I get the FPGA going I can interface what you are developing to it easily.

On a personal note I have met you at a couple of Unoffical Propeller Expos and I believe we both live in the same state. Keep us informed on your progress.
2X Timex Sinclair 1000, ZX81, ZX80Core, 5X 16K Ram Pack, ZXBlast, ZX P file to Ear Input Signal Converter, Elf II

tdg8934
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Re: New hardware I/O board using Parallax Propeller

Post by tdg8934 » Tue Jul 30, 2019 3:56 pm

Blitted - I have met you before a few years ago I think in Ohio for some computer users group (C64 like single board parallax computer I think).

I have a Nano DEO FPGA that I used once with an RGB LED display project I wanted to re-create. I heard they were being used to emulate a Propeller II. (Tim)

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Re: New hardware I/O board using Parallax Propeller (VGA,Sound,Joystick,etc)

Post by Bean » Wed Aug 07, 2019 2:00 pm

I am working on the VGA modes and I was wondering what everyone thought would be good modes to have for games and such.

I have about 16K for video memory and maybe another 2-4K for palette info. So with that in mind here is what I came up with.

Text:
80x25 (not sure about what is possible for colors)

Graphics:
640x200 2 colors (every line can have a different 2 color palette out of 64 possible colors)
320x200 4 colors (every line can have a different 4 color palette out of 64 possible colors)
160x100 64 colors (every pixel can have any of the 64 possible colors)

Do you think these are useful modes ?
Maybe a 256x192 2/4 color mode ?
All of these mode have only 1 page. Should I make some lower resolution modes that have 2 pages for page-flipping ?
Keep in mind that the ZX81 can run in FAST mode, so even though there is a lot of screen memory the ZX81 will be pretty fast.
In SLOW mode you will have a dual-screen setup. The VGA cannot be used with the normal PRINT, LIST, and INPUT commands.

Thanks for your input,
Bean

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Re: New hardware I/O board using Parallax Propeller (VGA,Sound,Joystick,etc)

Post by Bean » Fri Aug 09, 2019 2:23 pm

I haven't heard from anyone...
I have pretty much decided on:

VGA 640x200 2 color
VGA 256x192 4 color (2 pages for page flippin' games)
VGA 160x100 64 color

Stereo sound (3 voices+1PWM left, 3 voices+1PWM right)

Wii Classic Controller for joystick

I plan to offer it as a kit for about $100 - $150. All thru-hole parts.

All comments welcomed,
Bean

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mrtinb
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Re: New hardware I/O board using Parallax Propeller (VGA,Sound,Joystick,etc)

Post by mrtinb » Fri Aug 09, 2019 2:47 pm

Personally I think it's not interesting, as it will only work with software custom made for the device.
Martin
ZX81, Lambda 8300, Commodore 64, Mac G4 Cube

Bean
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Re: New hardware I/O board using Parallax Propeller (VGA,Sound,Joystick,etc)

Post by Bean » Fri Aug 09, 2019 10:13 pm

mrtinb wrote:
Fri Aug 09, 2019 2:47 pm
Personally I think it's not interesting, as it will only work with software custom made for the device.
True, that is a fair point.

The advantage is that you can run the ZX81 in FAST mode, which really unleashes the speed. Machine code is crazy fast..

I don't plan to sell a bunch of these. It is more or less a labor of love.
Even though it won't have any ROM code, I'm trying to make it BASIC friendly.

I have decided to name the module the "ZXGame Interface". I started a facebook group with that name if anyone is interested.

I removed the RAM and added a pass-thru so it can be used with the ZXPand. Maybe that will entice some people to create some games for it...
You do need to disable RAM in the 8K to 16K region (that is where the ZXGame "lives").

Bean

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Re: New hardware I/O board using Parallax Propeller (VGA,Sound,Joystick,etc)

Post by nollkolltroll » Sun Aug 11, 2019 7:52 pm

My small opinions:
- Keep the "colour" modes greyscale to fall in line with the ZX81 spirit. A ZX81 with 2-bit greyscale would look lovely, just look at the GameBoy. Easy to use a composite video out with the new modes as well as the VGA in parallell.
- It is VERY good to use the 8-16k area, so the zxpand can add another 32k.
- A lower colour mode for 160x100 would also be nice to have double buffering.
- The price point will make it a hard sell for many enthusiasts, along with the no-existing-software-yet. I'm not saying it is not worth it, but figure on low sales.

Other than that: happy hacking, I will cheer you on!
/Adam

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Re: New hardware I/O board using Parallax Propeller (VGA,Sound,Joystick,etc)

Post by 1024MAK » Sun Aug 11, 2019 10:24 pm

Bean wrote:
Wed Aug 07, 2019 2:00 pm
I am working on the VGA modes and I was wondering what everyone thought would be good modes to have for games and such.

I have about 16K for video memory and maybe another 2-4K for palette info. So with that in mind here is what I came up with.

Text:
80x25 (not sure about what is possible for colours)
Yes, I’d like an eighty column mode. Colours not that important, but maybe it would be possible to have a attribute system like on the ZX Spectrum?
Bean wrote:
Wed Aug 07, 2019 2:00 pm
Graphics:
640x200 2 colours (every line can have a different 2 color palette out of 64 possible colors)
320x200 4 colours (every line can have a different 4 color palette out of 64 possible colors)
160x100 64 colours (every pixel can have any of the 64 possible colours)
Do you think these are useful modes ?
Yes :D
Bean wrote:
Wed Aug 07, 2019 2:00 pm
Maybe a 256x192 2/4 color mode ?
Yes :D
Bean wrote:
Fri Aug 09, 2019 2:23 pm
I haven't heard from anyone...
Sorry, have only just got to this... :oops:
Bean wrote:
Fri Aug 09, 2019 2:23 pm
VGA 640x200 2 color
VGA 256x192 4 color (2 pages for page flippin' games)
VGA 160x100 64 color

Stereo sound (3 voices+1PWM left, 3 voices+1PWM right)

Wii Classic Controller for joystick

I plan to offer it as a kit for about $100 - $150. All thru-hole parts.
Looking good :D
nollkolltroll wrote:
Sun Aug 11, 2019 7:52 pm
My small opinions:
- Keep the "colour" modes greyscale to fall in line with the ZX81 spirit. A ZX81 with 2-bit greyscale would look lovely, just look at the GameBoy. Easy to use a composite video out with the new modes as well as the VGA in parallell.
- It is VERY good to use the 8-16k area, so the zxpand can add another 32k.
- A lower colour mode for 160x100 would also be nice to have double buffering.
- The price point will make it a hard sell for many enthusiasts, along with the no-existing-software-yet. I'm not saying it is not worth it, but figure on low sales.
I have no objection to having a grey scale palette, as long as there is also a colour palette, at least for the 64 colour mode.
If possible, it would be good if it can work with ZXpand.
Of course a lower price would be nice, but it is what it is. The Chroma 81 Interface is an excellent device that is not cheap and also awaits for software to be developed for it.
I still bought one. Because, well, apart from the existing basic ZX81 hardware, if no one develops anything new, progress will be limited. Sooner or later, some new software may be developed, and you never know what will happen then.
So yes, I’m up for it. Plus I like playing with new bits of kit :D :lol:

Mark

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Re: New hardware I/O board using Parallax Propeller (VGA,Sound,Joystick,etc)

Post by Bean » Tue Aug 13, 2019 1:44 am

Using the existing 4 color mode and just setting the palette to the 4 gray scales in the 64-colors available would create a 2-bit grayscale screen.

The price could be less than $100, but I'm not sure just yet. Might be as low as $50 for the kit. I will have to see.

Again, the big advantage of the board is that you run (or can run) the ZX81 in FAST mode.

Bean

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