[Coco] VCC 1.40 emulator issues

[Roger Taylor]

To Joseph Forgione,

I didn't have your e-mail handy, so I posted to the list in case 
you're lurking.

I hope you're planning on an update of the VCC CoCo 3 emulator.  If 
so, here are some things I'd like to see:

Mimicking of the "unavailable hardware port" read values.  Some 
CoCo's read back 126 decimal if a port is not there, for 
example.  I've never really seen a CoCo report 0 when a port is 
missing.  Some software peeks at a port, and/or writes and reads back 
the value to determine whether a device is plugged in.

Also, writing to an FDC register keeps reading back 0.  On my CoCo 3 
with Super Controller, writing to 65353 (track register) will read 
back the same value, letting me know the FDC is available.  So, my 
CoCoNet ROM (Disk BASIC 1.1 replacement) can't detect the FDC from 
VCC using my current method.

How would I go about writing a DLL that could mimick my Drive Pak or 
Wireless Pak?  Each pak contains the CoCoNet ROM (16k) and a 6551 
ACIA.  I'd have to write the MicroDrive emulator in the DLL that 
somehow accesses up to 2G of storage on the PC and talks back to the 
CoCo just like the real MicroDrive module does.  I'd want the DLL to 
completely emulate the Drive Pak so I, and others, can build up the 
floppy disk and hard drive images within a 2G MicroSD image file and 
then write it to the card later using some card imaging tool.

The MicroDrive module talks over a serial link with the 6551 at 
230400 bps (I use a double speed crystal), so the Drive Pak DLL file 
would be almost like the RS-232 Pak DLL but with my CoCoNet ROM in 
it, and the addition of code for listening over the 6551 TX line for 
commands and responding back like the MicroDrive does.

-- 
~ Roger Taylor