archive.worldofdragon.org

Hi all, Was the disk with the modules that would allow a custom OS-9 install ever released? What I'm looking to do is build a custom OS-9 boot disk with some updated / changed modules (specifically disk and clock). Yes I know about Nitros9, but I'd also like to backport my work to "official" Dragon ...

Are both CPU's really running code from the ROM at the same time? Wouldn't that cause conflicts on the data bus? Is CPU#1 ever HALTed? The current code has a comment saying FIRQ goes to both processors, confirmed by your notes, but the old working emulation never seemed to do this. I'll see if I ca...

Does the Dragon MMC come with a case ever, or will I have to make one from Lego? I've uploaded the source for the DragonMMC firmware to my github repository here : https://github.com/prime6809/DragonMMC There is a folder with the FreeCAD source and generated STL files that will allow you to 3d prin...

The emulation of the Beta last worked in MESS 0.138, which was 10 years ago! The MAME framework has advanced significantly since then but the Beta driver has been left to rot. I'd really like to get the Beta emulation working again, but will require more or less a rewrite to make use of the latest ...

For what it's worth this is the code that the diag card uses to identify the 6309. ; ; Test to see if CPU is a 6809 or 6309. ; ; GetCPUType ; lbsr LCDClrScr ; clear LCD screen leax LCPUIs,pcr ; point to message lbsr DevWriteStr ; write it ldb #$ff ; setup b FCB $10 ; This will be CLRD on 6309, CLRA ...

CoCo 1 has 5V,12V *AND* -12V. Dragon has 12V and 5V CoCo 2,3 have only 5V. What is important though is the line that carries -12V on the CoCo1, carries +12V on the Dragon. Though unless you are using them they can be left unconnected. Certainly for a ROM cart you shouldn't need them. Cheers, Phill.

A Dragon 32 board I thought was dead magically came back to life for as long as I held a probe to the RESET line on the CPU - turned out that pin was just not making a good connection in the socket! I had a problem almost identical to that on one of my Jupiter Ace boards except it was IIRC A8 of th...

Reg3 looks like it has the insulation kit there, I think it consisted of a piece of mica? and an insert washer for the screw hole, along with some thermal paste (the white stuff round it).

Something like this : https://uk.rs-online.com/web/p/heatsink ... s/7128225/

Cheers.

Phill.

robcfg wrote: ↑Sat May 23, 2020 12:30 pm That's nice, thank you!

I'd add a Gotek floppy drive emulator to the list.

That's effectively what DragonDrive is isn't it? A DragonDOS cart with built in Gotek running flash floppy.

Cheers.

Phill.

Yeah Dragon/Tandy and BBC analog joysticks do theings the correct way a potential divider, which is wy you never have to calibrate them because they are in effect self calibrating. However to read them you need to be able to read the voltage level which means some sort of DtoA and a comparitor. The ...