data bus

[sciguy125]

Has anyone looking into trying to implement an external data bus for the RC? I've been thinking about it, but I've come up against some big limitations.

The first is that the digital I/Os are filtered. I think I figured that the regular ports would get ~10 bytes/ms with an 8bit wide parallel bus. Using the interrupt ports (with a higher pass filter) would require a serial bus because of their limited number. I figured that it'd get about the same data rate, but would also require control bytes. Essentially, no real gain, but with much more complexity.

The next options are the serial ports. The TTL port is out of the question because it would eat the camera's interface. This leaves the program port. My main concern is that it would eat the RC's main debugging port. Actually...what would happen if more than two devices are connected to this port? Say that the bus controller is on the same port (split cable), but has a command set that would have it ignore any traffic between the RC and a PC. Of course, the conflict resolution would be really nasty. There's also the option of passthrough; flag the bus traffic and pass anything else.

Sorry for the rambling, I just want to get ideas out.

Ideas/comments?