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Adjustment procedure is as follows I believe. There are two variable resistors and a variable cap to tweak. Pull the WD2797 pin 22 to GND to force it in to test mode. You now need to adjust three timing / frequency values. Firstly the main data separator clock This is done by looking at the VCO cloc...

Hi D64UK, You'll not have any luck swapping the ROMs over... they are different pin counts and pinouts - Dragon 32 uses 2x8k 24 pin mask ROMs, Dragon 64 uses a pair of 16k 28pin EEPROMs. And the initialisation code which brings the machines up differs between the two ROMs as well. Can you post a vid...

Yeah, that does look pretty much OK, perhaps it's not directly related to a doublesided format as I'd assumed, Something must be amiss though to explain the Xroar vs Mame discrepancy in behaviour.

It appears that Mame Dragon disk drive emulation is broken for some non-standard disk formats as well. Soren's 80 track OS9 system disk image (.VDK) works great on Xroar. https://www.roug.org/retrocomputing/os/os9 But it fails to get past loading the boot track on Mame. Most likely because double si...

Uses a 6821 to interface the 14B multibutton voltmace joystick...

https://www.facebook.com/groups/dragon3 ... 985205629/

A bit of disassembly of the ROMs and then some searching on here... CLS 9 switches the G0 value in text mode and determines whether character set 0 or 1 from the ROM is used. It stores details of the mode setting in bit 4 in zero page $77. This isn't switching INT/EXT character set. Sixxie and co al...

Have a look at the DOS command. I think this does a two byte read, to check for the presence of the boot track signature. So a one byte read, or any other number should be possible, assuming you only want to start at the beginning of the sector. I don't think the disk controller is able to allow pre...

I unbundled Telepost System's Terminal Simulator cartridge for the Dragon 64 into just an ordinary OS9 application that can be run from disk. It's here: http://archive.worldofdragon.org/phpBB3/viewtopic.php?f=5&t=5781 The original ROM cartridge image is attached. I can't locate it in the Archive, so...

Here's something I've been meaning to post for a while. Duncan Smeed brought a little bare cartridge board along to the Dragon meet last year which when plugged into a machine booted straight Telepost Systems 'Terminal Simulator'. A little inspection of this program suggested the cartridge was on OS...

Here's a version of the minted WYSIWYG editor which I hacked together for the 80 column DragonPlus screen driver...

I had a copy of this running briefly on Tony's DragonPlus machine at the Dragon meetup last year, but I don't think I posted it anywhere.