[Coco] Micro SD CoCo

[Joel Ewy]

This is very cool, Roger.  To make it super ultimate cool, one would use 
a CPLD or something like that to mimic the register set of the FDC, and 
have the CPLD (maybe would need the help of a little PIC) communicate 
with the flash memory.  This would be a true replacement for the floppy 
drive, and would work with all software.

Just a thought...

JCE

Roger Taylor wrote:
>
> 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.