[Coco] Dragon & Drivewire

[Luis Fernández]

Hello allam very interested in the subject you touch

In this regard
> One thing I did wonder is why the coco1 is limited to 33K Whereas the> CoCo2 and the Dragon can reach 56K It Seems? Is this due to the CoCo2> Having better transmission than the coco1 circuitry, IIRC Which uses> Op-amps as level shifters. If this is the case then the retro-fitting> MAX202 circuit to to enable it to coco1 Also might reach 56K. I'll give> This a go at some point.
I think the problem is that the coconut was bringing 4k, 16k, or 32k and the rest was rom and ram but could not get more ram for basic, in coco2 already has 64K actual basic and improved ram which changes to rom while running and let free to 56k basic, the coco1 could do if placed 64k basic + 1.1 (basic + extbasic of coco2) simply (I think, correct me if I'm wrong)





> Date: Fri, 12 Oct 2012 11:51:38 +0100
> From: afra at aurigae.demon.co.uk
> To: coco at maltedmedia.com
> Subject: [Coco] Dragon & Drivewire
> 
> Hi all,
> 
> Earlier this week I managed to boot my dual personality Dragon 64 (using 
> the CoCo2 roms) over Drivewire, using a simple level converter circuit 
> which takes the 3 lines used by the bitbanger and converts them to RS232 
> voltage levels (Max202).
> 
> I was able to boot at the 56K baud rate, and everything seemed to work 
> fine.
> 
> One thing I did wonder is why the CoCo1 is limited to 33K whereas the 
> CoCo2 and the Dragon it seems can reach 56K ? Is this due to the CoCo2 
> having better transmission circuitry than the CoCo1, which IIRC uses 
> op-amps as level shifters. If this is the case then retro-fitting the 
> max202 circuit to a CoCo1 might enable it to also reach 56K. I'll give 
> this a go at some point.
> 
> Next up I guess is to take the DW bitbang routines out of HDB-DOS ans 
> see if I can insert them into SuperDos, as this would allow the Dragon 
> to natively use a DriveWire server. Though the complicating factor here 
> is that DragonDos & SuperDos, unlike RS-DOS allow 4 different disk 
> formats SS40, SS80, DS40 and DS80. The problem being of course that SS80 
> and DS40 are the same size :( NitrOS9 handles this because it just uses 
> LBA rather the CHS.
> 
> In other news, I now have DragonMMC working on the CoCo, this is able to 
> load cas files by patching the ROM to load from the MMC card, so a 
> typical cas game loads in a couple of seconds. Since it also has 32K of 
> ROM, it can soft load cartridges, this is how I booted over DW, 
> sofloaded the HDB rom and then typed DOS.
> 
> Cheers.
> 
> Phill.
> 
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