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Hi all, As I'm simultaniously working on both the AtomColour and the DragonRGB, which have a lot in common. On the Atom I'm just taking the Y input from the onboard two transistor Amplifier, and feeding it into Hoglet's clamping circuit and that seems to work quite well. On the Dragon I have had to ...

danielj wrote: ↑

Mon Mar 18, 2019 8:58 pm

Should do, yes. Or you can use any PC floppy drive (you might have to change the jumper - sometimes a 0ohm resistor - to make it drive 0 though!)

Or use a cabe with a twist between pin 10and 12.....note not the same twist as a PC cable, but works the same way.

Cheers.

Phill.

bprosman wrote: ↑

Tue Mar 05, 2019 10:26 am

Hi Phill,

What toolchain do you use to compile the Keyboard (AVR) files ?
Atmel Studio ? Or "native" AVRgcc ?

Usually the AVRgcc toolchain, I'm on windows so I (historically) installed WinAVR, and then updated it with the more recent Atmel command line package.

Cheers.

Phill.

ask_nz wrote: ↑

Sun Mar 03, 2019 6:49 pm

Hi Phil,

*COUGH* Phill *COUGH*

What do you use to program your CPLDs?

Xilinx webpack and one of the clone Xilinx usb programmers like the one shown on hoglet's wiki page here : https://github.com/hoglet67/AtomBusMon/ ... requisites

Cheers.

Phill.

Looks good, you have : 6K of CPU RAM, 2K of video RAM, Both integer & floting point ROMS. You don't have the printer port, bus buffers or 6522 fitted. And it looks like someone tried ignoring the advice in the Dragon manual not to feed coputers Tea and Coffee....... You do have the video header fitt...

And the award for the most expensive Electon system goes to :

https://www.ebay.co.uk/itm/lolprice/254109643297

Phill.

roland wrote: ↑

Sun Feb 24, 2019 7:35 pm

don't worry, Atom parts are easy to get and quite cheap. As long as the main board is in good condition all will be fine

Seconded all reasonably standard chips, weirdest ones are the 8304 and 81LS95, though I think the beeb also uses the latter.

Cheers.

Phill.

Awesome stuff! Does your board have a place for an external character eprom? The version on FB doesn't as it's actually just the Atom board re-purposed....but the Dragon specific version will....first spin currenly on order. I did also considder this for the Atom version, but needing to fit it insi...

And now the Atom board is working in the Dragon.....

https://www.facebook.com/media/set/?set ... c310b7126f

Album should be visible to all even without a FB account.

Cheers.

Phill.

My first comment on the joysticks and using NES/SNES sticks, yep it may save you on I/O but at the expense of added complexity and severly limiting what is available to the end user. If you want to limit the I/O used mux the two ports and use the Sega Megadrive scheme which essentially muxes the add...

DutchAcorn wrote: ↑

Thu Feb 14, 2019 5:19 am

This looks really good! I’ll get my Atom out over the weekend and see if I can also remember how to program the video card...

Be careful, the above posted firmware is for the 5.10 board, but if you have one of those you should be good to go.

Cheers.

Phill.

...it worked! I remember being really surprised the first time, because out of a set of controls that look like they might drive a nuclear power station, you click on one and it pretty much instantly completes the job! Yeah the Xilinx software is a little like that, what is a reall pain in the ass ...

Or a 6309, which is a 6809 on steroids! From our benchmark on the Dragon Archive (see http://archive.worldofdragon.org/phpBB3/viewtopic.php?f=5&t=5567&hilit=6309#p17017 ), the 6309 is roughly 3 to 4 times faster computing Pi digits. 3 to 4 times faster than the 6809? Mind doen't supprise me as it d...

I always thought, looking at the Tatung Einstein, that it was strongly inspired by the BBC, both in the connectors available and the naming of some of them. It of course runs on a Z80. Now how about a 6809 based beeb? Basically the same bus so a lot of the electronics could be the same, but without ...

Beebs, Atoms, Dragons, actually a couple of my QLs don't have the top half screwed on either.......Neither does the Nascom, but it didn't have any screws when I bought it so that kinda doesn't count.....

Starting to see a pattern here......

Cheers.

Phill.

Hi all,

If you have the ability to re-program the CPLD, then try this set of firmware it hopefully will fix the sync issues in the 5.10 board.

I've tested with Acornsoft Invaders & Flappy bird, and both seem fine.

Let me know how you get on.
Cheers.

Phill.

This is all sounding very encouraging. Hopefully so.... On my machine one of the most badly-affected games is Flappy Bird, which is colour. If the problem really is noise, what could the mechanism be for generating more noise when running specific games I wonder? I'll give flappy bird a try, does i...

Right, I've tried the syncronous reset and it seems (crosses fingers) to be much better, though I've gone back to counting HS pulses. I'm sure this was the way it was origionally, however I've since implemented a 2 stage latched /hs and am using that as the clock for counting the pulses, as that's w...

screen.png This is my scope trace of what is happening. 1:Yellow is latched HS xor FS 2:Cyan is the FS input. The scope is set to trigger on the falling edge of this signal 3:Magenta is the HS input 4:Blue is the generated sync signal. This sync is in the approx correct** place, when the problem oc...

Hi all, I'm really stuck with this, there is a problem with the AtomColour 5.x boards where the sync is lost momentarally leading to the video image jumping. I generate the sync in the CPLD and have tried two methods so far both of which seem to exhibit this problem. Method 1: Wait for /FS to go low...

flaxcottage wrote: ↑

Wed Feb 06, 2019 1:01 pm

If I can get the demo set up in time I'll also bring a Plotmate A4 set up and LOGO.

Wonder if anyone will use it to draw a giant willy I was kinda surpprised no one did that when we where playing with turtles a couple of years back

Cheers.

Phill.

I might be persuaded if there will be beer the night before......
And assuming it doesn't clash with my other event in April.

Cheers.

Phill.

Kazzie wrote: ↑

Tue Feb 05, 2019 3:20 pm

Whatever the suffering of the Electron, that ZX81 now has a much nicer keyboard fitted to it.

Now if only I could get my model M working with my ZX81.....actually I prolly cood if I made a ZX81 -> PS/2 keyboard interface.....

Cheers.

Phill.

This is not my area, but I know someone who had problems with fast modern RAM (not in an ATOM), because it was fast enough to interpret noise as signals that the older RAM didn't seem to notice. That's the reason that I've had to implement a write strobe gate, as when the 6502 was de-selecting the ...

It's a ZX81! Surprisingly, the Elk's keyboard matrix is almost the same as the ZX series (ignoring the extra keys). So, just a little surgery would move the ENTER, Shift and SPACE keys I did wonder about that there are some pictures in the auction of the underside of the keyboard and I was surppris...

Are you sure it's Acornsoft Invaders because there was a glitch in Bug Byte Invaders: https://stardot.org.uk/forums/viewtopic.php?f=44&t=7320&p=112775&hilit=invaders+glitch#p112775 Seems that during keyscan, the mode is switched to CLEAR0 for a few msec. Yep that could screw things up :( But later ...

I wonder if you are getting brief periods of bus conflict between the RAM and IC29 (the 8304 buffer). That is possible, expecially with my write gating activated, but it does it even when just using the /WE pin from the RAM socket. I am planning to maybe also drive /OE from the CPLD, so that /OE is...

jms2, What RAM chip is on your Colour board? Just found something interesting playing with the new version....... With a CY62256 55ns 32K RAM on there I get the problem of the sync jumping about. With a 6264 made by RCA, I think it was harvested off a Slogger Turbo board....thanks Arcadian :) It's a...

https://www.ebay.co.uk/itm/333051288997

Phill.

I've done some more investigating on the vsync issue..... No longer seeing it in "Cowboy shootout" but I am seeing it in Acornsoft "Invaders", oddly only when it's in mode 4, and moving the invaders on the screen. Now simultaniously with doing this it will be reading the keyboard and producing sound...