As you can see in my previous mail I found out how the VMU to VMU
communication works. I now need opinions about connecting a VMU to a PC. My
currently used hardware is built around an Atmel AT90S8515 microcontroller
for synch/async conversion. It is connected to the RS-232 serial port on a
PC. One of my questions is if I should rewrite most of the software,
contruct a pcb layout, document and release it or if I should think about
an easier hardware to connect the VMU to the PC? To build the current
version people have to be able to etch their own pcbs (most likely single
sided) and need a programming cable/software for the Atmel. All the
software I have written for it is Linux specific and not easy portable,
although I think I could make an Amiga version, too. I doubt that the
hardware will support the VMU to DC communication mode without major
hardware changes. This is a major problem since I think this communication
is more powerful and faster than the VMU to VMU communication. An easier
hardware still needs to convert the 5V logic to 3V, although most modern
PC parallel ports are already 3V, I think. This problem will vanish as soon
as somebody finds out that the VMU inputs are 5V tolerant. Another problem
is that most modern OSs support multitasking, so getting a reliable timing
is nearly impossible. The main reason why I chose the VMU to VMU
communication for my interface has proved to be wrong: even with the simple
VMU to VMU protocol it is possible to generate errors which require
reinitialisation of the VMU on a DC. Or is there a way to reformat the VMU
without a DC?

When connecting the VMU to a PC a connector is needed. So does anybody know
a source for those connectors? My current solution is a pcb with the
innards of a VESA local bus connector, anybody got other ideas?

Best regards, Soeren

PS: I just read the documentation on Marcus page about the maplebus, I will
need to make some experiments, but I think this is the way to go.