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
Bean
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Joined: Fri Aug 01, 2014 8:40 pm

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

Post by Bean » Wed Jun 12, 2019 12:23 am

Hey guys,
I'm working on a new hardware project. An I/O board for the ZX81 based on the Parallax Propeller.
I want to keep it very simple and able to be made from all thru-hole parts.

It's a very simple board with the propeller being fast enough to handle all the bus timing.

Anyway, it currently is working as a set of 128 16-bit registers that can be written and read.
It currently has 8 I/O bits, but I think I can get 10 I/O bits.
It is memory mapped (so you can just use POKE in basic) into the 8K to 16K region.
POKE 8192,write register (0 to 127)
POKE 8193,set LSB
POKE 8194,set MSB

POKE 8192,read register+128
PEEK 8193,read LSB
PEEK 8194,read MSB

Right now register 0 is the I/O port, and register 1 generates a tone.

The propeller is able to do a lot of things since is has 8 32-bit processors and 32K of memory.
So what type of things would you guys like it to do ?
Here are some things I thought of:
' Sound
' Speech
' Serial In/Out
' VGA terminal
' Composite Video terminal
' Keyboard terminal (not replacing ZX81 keyboard :( )
' Joysticks
' Temperature Sensor
' EEPROM
' Simple Light Pen
' IR send/receive

I only have 10 pins, so I can only implement so many things.

Also, does anyone know where I can get the edge connectors ? I really don't want to have to modify them if can avoid it.

Thanks for the input,
Bean
Last edited by Bean on Wed Aug 07, 2019 1:53 pm, edited 1 time in total.

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

Post by tdg8934 » Wed Jun 12, 2019 3:20 pm

Hello Bean - It's been a while (Tim Gilmore).

You can try to get the edge connectors at this site: https://www.sellmyretro.com/offer/detai ... ck%29-3823

I had (may still but need to check tonight) a couple of them I got from PokeMon a few years back.

Your project sounds really interesting and I would love to hear more. Do you have a ZXPand+ board? If not you should get one (or I can let you borrow mine). It has serial I/O out that I have successfully connected to a Parallax LCD display. There is a post on this site about it somewhere.

I wish the Parallax SX28 didn't go away so many years back. Your video cards were great and fun to work with!

Let me know if I can help in any way.

Tim

Bean
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Joined: Fri Aug 01, 2014 8:40 pm

Re: New hardware I/O board using Parallax Propeller

Post by Bean » Wed Jun 12, 2019 3:53 pm

Hey Tim,
Yeah I saw them, but they are "out of stock".
I tried modifying a longer connector, but I made a mess of it. It's good enough to test with.
I am really just wondering what connectors to put on the board, RCA, VGA, etc.

I think it will also have a row of pin so you can connect a daughterboard to do other things.

Bean

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

Post by tdg8934 » Wed Jun 12, 2019 8:04 pm

Bean,

I don't know if it's possible with your setup but I would love to see "Color" VGA" or composite video out of the TS1000/ZX81 perhaps something like the Chroma81 does with SCART for those in Europe - http://www.fruitcake.plus.com/Sinclair/ ... erface.htm.

Tim

Bean
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Joined: Fri Aug 01, 2014 8:40 pm

Re: New hardware I/O board using Parallax Propeller

Post by Bean » Wed Jun 12, 2019 9:05 pm

It could make VGA or composite video, but it would be an independent screen (it would not be a copy of what is on the normal screen).
This is because I don't have enough address lines to monitor that much memory (I only have access to 4 addresses).

LIkewise, with the keyboard. It could support a PS/2 keyboard or mouse, any your program could read it, but it would not be able to enter programs.

Bean

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

Post by mrtinb » Wed Jun 12, 2019 10:39 pm

Seems like someone already made ZX81 VGA output with a Propeller.

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

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1024MAK
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Re: New hardware I/O board using Parallax Propeller

Post by 1024MAK » Thu Jun 13, 2019 2:15 am

I’m not sure if there is another source for ready made ZX81 edge-connectors, but I posted some sources for ZX Spectrum ready made edge-connectors over on Spectrum Computing forums.

Mark

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

Post by tdg8934 » Thu Jun 13, 2019 2:38 am

Bean,

I have a zx81 edge connector soldered to a short extender board with solderable holes for a connector between (I have 2 connectors you could solder in). I also have an unsoldered edge connector that you would have to cut down a few spots. I can mail them to you for free if you want. Just PM me your address. I live near the Chicago area in Illinois. Enjoy! Tim

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

Post by Bean » Thu Jun 13, 2019 2:56 am

Tim,
Thanks for the offer. I'd like to find a source for the proper connector because I would like to sell these as a kit.
I'm using all thru-hole parts. If it is popular, I might redesign for surface mount parts and sell it already built.

After I get the design finalized I'd like to send you one to alpha-test. Are you familiar with the Propeller at all ?

Bean

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

Post by mrtinb » Thu Jun 13, 2019 7:05 am

The connector is not made any longer. So we all buy ISA connectors and cut them to the right size.
Martin
ZX81, Lambda 8300, Commodore 64, Mac G4 Cube

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