DigicoolThings Forum

Here is an image of the system running the Christmas Demo:



I don't really have a good workspace so it's on our coffee table and the dodgy little monitor I have doesn't actually stand up properly when cables are plugged into it (BTW the VGA cable isn't actually used - it's still plugged in from when I was playing with another device) - and it doesn't show colour very well unless you are looking right at it. Anyway, quite pleased that so far almost everything is working perfectly - I was really worried that I may have messed something up installing the board behind the VDP but that seems to be working fine. Now I'm just waiting on that sound chip replacement.

epaell wrote: ↑Sat Mar 30, 2024 9:15 pm ... Anyway, quite pleased that so far almost everything is working perfectly ... Now I'm just waiting on that sound chip replacement.

Awesome! It's great to see someone else's system up and running. Having the sound will finally round-out the Christmas Demo.

I recently got a similar small monitor from AliExpress. It is Eyoyo 10 Inch IPS 1920x1200, with HDMI / VGA / Composite and inbuilt speakers. Seems to do okay, after I mounted it on a more robust stand. My only niggle is the screen on it is highly reflective, but otherwise, these small monitors are really useful for retro project display!

The sounds chips arrived in the mail this morning and the first one off-the-bat worked a treat (can also confirm that my mutilated version of your Christmas demo code to test just the sound chip without using the VDP also works). I now have a fully working system ... LOL, and 9 spare sound chips (the bundle I got was even cheaper than the first lot I got) ... and two dogs that are apparently not great fans of 8-bit music!

epaell wrote: ↑Tue Apr 02, 2024 12:42 am The sounds chips arrived in the mail this morning and the first one off-the-bat worked a treat (can also confirm that my mutilated version of your Christmas demo code to test just the sound chip without using the VDP also works). I now have a fully working system ...

Great news!

epaell wrote: ↑Tue Apr 02, 2024 12:42 am ... and two dogs that are apparently not great fans of 8-bit music!

Perhaps they were just celebrating the success!

A quick update on progress ...

I was playing a bit with the graphics card yesterday and managed to convert the plasma code from Matt Sarnoff's page https://github.com/74hc595/Ultim809

https://youtu.be/UL60HAnd0NA

I might have to look at his asteroids game as well to see if I can port it across. The main sticking point is the different audio device used (AY-3-8910 equivalent) and my lack of a controller/joystick (though that should be easy enough to add to the PIA Port once I have one).

I just noticed the update to the 6809 CPU board that you posted and actually had a thought for the I/O card - it would be convenient to have a more standard IDC header for the serial line pins and perhaps add additional GND and +5V pins similar to what the PIA IDC has. It would make it convenient to power any serial devices that are used to connect to the outside world (and easier to find good solid plugs for the socket). At the moment I have a number of Arduino-style cables hanging off the PIA port and the ACIA port to drive my serial device and it is a very tenuous connection. LOL, having an AY-3-8910 would also be really cool as it is used by a lot more software but it is a really big guy and I recall that you originally wanted SN76489 to make the hardware similar to the Dick Smith Wizard.

BTW, I also been playing with an alternative to convert the RGB to HDMI:

https://www.amazon.com.au/dp/B07Z5W7QS7 ... ct_details

It's obviously not as flexible as the GBS but is smaller and cheaper (and doesn't require the modified SCART cable).

epaell wrote: ↑Sat Apr 13, 2024 9:52 pm I was playing a bit with the graphics card yesterday and managed to convert the plasma code from Matt Sarnoff's page

Nice work! I seem to be too involved in hardware at the moment, which is taking my attention away from coding.

epaell wrote: ↑Sat Apr 13, 2024 9:52 pm I might have to look at his asteroids game as well to see if I can port it across. The main sticking point is the different audio device used (AY-3-8910 equivalent) and my lack of a controller/joystick (though that should be easy enough to add to the PIA Port once I have one)...
... having an AY-3-8910 would also be really cool as it is used by a lot more software but it is a really big guy and I recall that you originally wanted SN76489 to make the hardware similar to the Dick Smith Wizard.

Yes, I have the AY-3-8910 in mind already, to play with eventually. But you are right, that what drove me to the SN76489 first was thinking of the Wizzard (CreatiVision). Not to mention the size was a better fit for adding a sound option to my first I/O Card.

epaell wrote: ↑Sat Apr 13, 2024 9:52 pm I just noticed the update to the 6809 CPU board that you posted and actually had a thought for the I/O card - it would be convenient to have a more standard IDC header for the serial line pins and perhaps add additional GND and +5V pins similar to what the PIA IDC has. It would make it convenient to power any serial devices that are used to connect to the outside world (and easier to find good solid plugs for the socket).

The intention of the serial connector chosen, was to implement the FTDI cable format. Therefore, a reasonably standard 6-pin FTDI serial cable can be used. I have however left pin-3 unconnected. Pin-3 is typically Vcc, supplied with either 3.3V or 5V. As I understand this is normally supplied from the FTDI device end (to power the FTDI cable attached serial device - e.g From a USB to TTL Serial adapter), I thought it more appropriate to leave pin-3 unused.

However, perhaps it would be appropriate to provide a jumper to connect 5V to pin-3, allowing it be use as a 5V output (GND is already on pin-1), for powering external serial devices, as you mention?

epaell wrote: ↑Sat Apr 13, 2024 9:52 pm BTW, I also been playing with an alternative to convert the RGB to HDMI:
https://www.amazon.com.au/dp/B07Z5W7QS7 ... ct_details
It's obviously not as flexible as the GBS but is smaller and cheaper (and doesn't require the modified SCART cable).

Interesting, let me know how you get on. Including how the quality compares!

Related to this (and to continue with my current hardware focus theme), I've just finished updating the TMS VDP Card to now also support the TMS9918, which has Composite Video output (only). Yet to make a video / final test!

This then means that the one TMS VDP Card will now provide support for all flavours of the TMS VDP chip, and allow those (mostly in the NTSC market), who are more familiar wih the TMS9918 variant, to ustilise the VDP Card.

As I'm in the PAL market, and I personally have a preference for component video quality, the TMS9929 always had my initial attention.

Thankfully I've never had to live with Never The Same Colour (NTSC) - I'm also in a PAL zone (Australia). I built a composite output version of the TMS VDP for the Arduino a while back and even got a basic version of Space Invaders to work on it

https://youtu.be/_vRySO5RH1w

but it was a complete hack and a nightmare to move around without connections coming loose (and I didn't really consider efficiency so it ran a bit slow).

BTW, I'm happy that you're hardware focussed because it means more goodies to try further down the line

I'll see if I can get some of my test and demo software in a Git repository so others can make use of it. I'd like to clean up the build system and the way bits are included to make it a bit more component-like but just haven't had the time to do it. At the moment I have an include file for ASSIST09 to provide utility macros for the SWI calls, one for the VDP handling and another for the sound device. But it's not tied together particularly elegantly or consistently at the moment.

epaell wrote: ↑Sun Apr 14, 2024 3:09 am I built a composite output version of the TMS VDP for the Arduino a while back and even got a basic version of Space Invaders to work on it...

That's awesome. Some fine work! I hope to have some Space Invaders running across the screen on an MECB system in the not too distant future. Of course, I'll also need to devise some controllers.

epaell wrote: ↑Sun Apr 14, 2024 3:09 am BTW, I'm happy that you're hardware focussed because it means more goodies to try further down the line

Yes, unfortunatley, life has been busy so far this year, so my time in my workspace has been limited. But things are starting to settle down.

epaell wrote: ↑Sun Apr 14, 2024 3:09 am I'll see if I can get some of my test and demo software in a Git repository so others can make use of it. I'd like to clean up the build system and the way bits are included to make it a bit more component-like but just haven't had the time to do it. At the moment I have an include file for ASSIST09 to provide utility macros for the SWI calls, one for the VDP handling and another for the sound device. But it's not tied together particularly elegantly or consistently at the moment.

Take your time, and release when you're ready. It's just great to have others experimenting and contributing to the MECB system. I have so many thoughts in my head of what I want to make and do with the system, but available time is also limited. At the very least, I've so far achieved my goal of recreating the 8-bit experimentation that I did in the early days, but this time using the updated, much quicker & easier to implement, framework provided by MECB (instead of what we did in the old days, with labour intensive one-off Wirewrap solutions on Eurocards etc).

A full complement of cards complete with v2.3 CPU card ... and a spare CPU card that I use for sanity checks (which came in useful when I was testing the ROM card):



I still don't have anything on the prototype board but I would really like to make something like micro SD storage card (akin to the Corsham Tech SD card for the old SWTPC computer). Unfortunately the person who used to make these passed away and the only other version I've found online requires working with SMD - and that is a bit beyond what I can do at the moment. I think I've found some Arduino modules that can greatly simplify the design so I'm going to try that first - I should be able to use the I/O card (sans sound chip, as I'll need some of the control lines that it sits on). Ultimate goal would be to boot up FLEX - which would open up a lot more possibilities (assuming I can ever find the time to do so).

Darn it - not sure why the image isn't working