EPP HAL Module|
Some thoughts for implementing the IEEE 1284 Enhanced Parallel Port protocol in HAL.
Here is a description of the EPP protocol: http://www.fapo.com/eppmode.htm
This protocol is used by Pico Systems' PPMC, and the (as yet nameless) Sanyo P5 BLDC servo driver board, being developed by various EMC users here: http://forums.donniebarnes.com/viewforum.php?f=16
And, fenn has been talking about building something like that for a while now; we'll see if he ever gets around to it.
How do you represent a serial communications scheme in a user interface that is primarily parallel?
1) hard-coded protocol, with n*hal_u32 inputs/outputs for encoder counts and separate hal_bit i/o for digital io
2)flexible protocol, with registers for each byte transmitted represented by hal_u8 pins (jmk dislikes this because it would be extra confusing, and useless for anyone but a driver developer who already knows how to write code anyway)