Search found 142 matches
- Sun Jun 13, 2021 12:42 am
- Forum: Dragon General
- Topic: DRAM data retention time
- Replies: 20
- Views: 44601
Re: the Delphi archives
Oh, that's unfortunate. Was fooled by the schematic which looks to suggest some spare capacity! Anyway a zip of the Delphi OS9 archives containing a 'drivepak' of those OS9 6809 system modules is on the Coco archive for download. So looks like I'll be downloading that and trying to figure out how to...
- Sat Jun 12, 2021 7:31 pm
- Forum: Dragon General
- Topic: DRAM data retention time
- Replies: 20
- Views: 44601
Re: Memory upgrade hijack!
I've gone old school with my upgrade: It's based on a design for the CoCo from the 80's that provides the extra address line required to drive 256K DRAMs fitted to the Dragon main board. The memory is banked in 32K pages, limiting your options as far as operating systems go, but still useful e.g. R...
- Sun May 30, 2021 4:00 pm
- Forum: Dragon General
- Topic: A DOSPlus Extender for Drivewire & CoCo-SDC
- Replies: 110
- Views: 111993
Re: A DOSPlus Extender for Drivewire & CoCo-SDC
The penny has just dropped... and I now understand a comment Pere made a long time ago in this thread... https://archive.worldofdragon.org/phpBB3/viewtopic.php?p=13766#p13766 To do the sector read/write data ready synchronisation, the CoCo uses HALT, which is not demultiplexed at all by the MPI, whe...
- Sun May 30, 2021 12:24 pm
- Forum: Dragon General
- Topic: A DOSPlus Extender for Drivewire & CoCo-SDC
- Replies: 110
- Views: 111993
Re: A DOSPlus Extender for Drivewire & CoCo-SDC
The !SCS/!P2 and !CTS/!R2 plus !CART signals are controlled by the lower and upper and nibbles respectively of the multipak control register, so it's possible to swap in the physical disk controller but keep the SDC ROM bank the same... From Ed's Mega Mini MPI design notes... The upper four bits of ...
- Fri May 28, 2021 6:33 pm
- Forum: Dragon Hardware
- Topic: Dragon expansions - FF00 page ports
- Replies: 8
- Views: 8582
Re: Dragon expansions - FF00 page ports
Voltmace Delta 14B multi-button joystick adapter !P2/!SCS FF40-FF43 6821 PIA, mirrored upto FF5F CoCoSDC (Dragon Mode) !P2/!SCS FF40 Emulated Disk Controller command/status reg. FF41 Emulated Disk Controller track reg. FF42 Emulated Disk Controller sector reg. FF43 Emulated Disk Controller data reg....
- Fri May 28, 2021 5:59 pm
- Forum: Dragon Hardware
- Topic: Dragon expansions - FF00 page ports
- Replies: 8
- Views: 8582
Dragon expansions - FF00 page ports
OK... a thread to accumulate info on Dragon FF00 page usage by expansions
- Mon May 03, 2021 2:13 pm
- Forum: Dragon General
- Topic: DRAM data retention time
- Replies: 20
- Views: 44601
Re: DRAM data retention time
Most interesting! So it seems that fixing the NHS signal on one of my Dragon64s was a bit of a waste of time then
- Fri Mar 05, 2021 12:55 am
- Forum: Dragon General
- Topic: Comparison of Dragon mass storage options
- Replies: 16
- Views: 25228
Re: Comparison of Dragon mass storage options
Updated to reflect Phil's creation of OS9 drivers for the DragonMMC...
- Sun Feb 28, 2021 12:10 am
- Forum: Dragon Hardware
- Topic: Experimental Blitter
- Replies: 8
- Views: 8400
Re: Experimental Blitter
Wow, very very cool! :o In this demo, is there any proportion of the CPU time that's free (not setup, and unhalted) cycles? Or have you filled the frame period to the brim? My mind is always drawn to all of the time on the bus available from the inside of the machine (AVMA and !E when outside of the...
- Sat Jan 09, 2021 8:06 pm
- Forum: Dragon Hardware
- Topic: Problems with DOS using an Y-type connection
- Replies: 42
- Views: 35678
Re: Problems with DOS using an Y-type connection
That's really excellent news!