[Coco] Micro SD CoCo
dml_68 at yahoo.com
Wed Oct 21 09:25:22 EDT 2009
Finally! I have seen the same thing for the Atari ST, Apple 2 and Commodore 64 and was hoping the Coco would follow with a similar system soon.
What kind of price point are you thinking of asking for this and is there a semi set release date?
** Mistrust Authority. Promote Decentralization **
--- On Tue, 10/20/09, Roger Taylor <operator at coco3.com> wrote:
From: Roger Taylor <operator at coco3.com>
Subject: [Coco] Micro SD CoCo
To: "CoCoList for Color Computer Enthusiasts" <coco at maltedmedia.com>
Date: Tuesday, October 20, 2009, 9:27 PM
Well folks, tonight I have the CoCo's first Micro SD pak. This is the same wireless pak model but with a different module plugged into the header. I just DSKINI'ed DRIVE 0 and saved 2 BASIC programs, typed DIR, and there they are.
In case you have never seen how small a Micro SD card is... it's about the size of your pinky finger nail. The module it slides into is also small and plugs into the Serial Pak's header but needs an adaptor to match the pins. Imagine hundreds of floppies, thousands of games and programs, and a full NitrOS-9 system instantly on power-up.
This is a serial-based virtual floppy system (CoCoNet) which works much like DriveWire, only there are no wires and the virtual drives are right there in the pak on that little memory card. I'm using a 2gig card for my tests.
The catch? The CoCo talks to the module @ 115200 bps over the 6551, so there will be some hard-coded Disk BASIC programs that require a real floppy controller and obviously won't work with a virtual drive system, but most programs DO run just fine.
I'm still fiddling with how to parition a card to share between Disk BASIC, OS-9/NitrOS-9 and whatever else. 2 gigs is an enormous amount of space for a CoCo system, so even if I have to use 1/2 of the card's 512-byte sectors, we're still good, although I don't want to waste any space like that.
In case you didn't read right... imagine a little game-pak sized cartridge with virtually everything for the CoCo on it! This will be the case when the pak is finished.
The EPROM "firmware" is a patched copy of Disk BASIC. It needs further tweaking to allow a mix of Drive Pak, Wireless Pak (either or both) without conflict, in a plug-and-play fashion. The CoCo will detect which pak(s) are inserted and communicate with the right module or PC server using the same protocol while allowing serial communications as well. Take a Serial Pak and plug what you want in the header, a bluetooth module or Micro SD module, and the pak should "work" as you expect using the same EPROM with no configuration.
Existing Wireless Pak users could swap out their bluetooth module with this Micro SD module and pop in the CoCoNet EPROM and be ready, or keep the wireless pak and insert a drive pak, but the paks need their own address, so the code has to detect which addresses/paks are present and automatically set things up when you turn the CoCo on.
As for NitrOS-9... I already have this booting over CoCoNet wirelessly so I'll just replace the protocol so that either a PC server or the MicroSD module will work the same... read and write sectors.
I do need to send off for a run of small header adaptors so the module will fit the Serial Pak. The header just matches a 1x5 header to 2x6 header, so it's going to be a tiny board with 90-degree headers on either end and some traces between some of the pins. In my test I use a breadboard with 4 wires run to it from the Serial Pak header. Ground, Tx, Rx, VCC. That's it.
-- ~ Roger Taylor
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