That user, and SCC parameters

[vk2xlz@gonzo.vk2xlz.ampr.org (Craig Small)]

G'day All,
  First of all, csmall@acacia.itd.uts.edu.au is me, I'll fix that little
thing up after this message.  Funny that he just didn't unsubscribe me
himself!

Next thing:  I'm trying to write a Linux driver for a PackeTwin (or is that
a PacekTwin driver for Linux?!?)  I've looked at the gracilis code and found
some strange things.  Now the PT uses a SCC, so others may help me.

When the SCC uses external clocking, it uses a line like
  "put TCTRxCP + RCRTxCP + TRxCBR in write register 11"
This means get my Tx clock from the TRxC pin, the Rx clock from the RTxC pin
and put the Bit Rate Generator output on the TRxC pin.
Now what is significant here is that there is no TRxCOI bit, so that the pin
is an input, which as this is for both external clocking is exactly what we
want.

My question:  To me the TRxCBR bit, in this use, is not required.  Am I
right or is there some subtle reason for this?

  - Craig vk2xlz