Sound like you are all in on the SB9600 interfacing. When I referred
> to "single ended", I should have said "not differential". There are
> points on the option connector that look like they connect to
> circuitry in the radio that does the same job as the SN65176BP. TTL
> TX/RX lines referenced to gnd, with busy (bidirectional signaling).
It does seem like it might reduce parts count if we tapped the SB9600
bus at a point where it's single ended. I haven't studied the schematic
yet to see where / if that's possible.
> I believe the much (much) slower, and higher pricepoint MiniMega2560
> has enough I/O for everything we want.
"Much slower" in this case means "about the same speed as the PIC on the
original Xcat -- roughly 1/8 the speed. The higher pricepoint is like
eight times the price of the Pico. It's a hell of a tradeoff for
getting 5V i/o, especially given how simple the necessary design appears
to be. I also suspect getting the Mega to work in the x9k version is
impractical: Skip said getting the timing right for the old X version
was tricky. Part of the idea here was to do a next-generation X device,
learning along the way, before doing an X9k device.
> How are you invisioning loading the initial codeplug data and
> maintaining the configuration?
If the X9kcat can emulate an eeprom, then the "how" doesn't really
matter -- RSS works, but so will anything else that can pretend to be
RSS. If it additionally has a command set accessible over some sort of
(probably serial) channel, whatever that may be, then there's an
additional way code plug data could be shoved in.
De
