On Tue, 22 Sep 1998, Dave Huang wrote:

> Ah, well that's what I meant... :) So we do support, for example, 23040
> baud? (3686400/2/16/(3+2))? Or 16457 baud? :) I guess that's not as useful
> as I thought it'd be though; I was thinking we did get one or two rates
> between 38400 and 57600 :)

We would be able to get 23040 (assuming your math's right :-). But we
don't get any rates between 57600 and 38400 though. :-(

> Do we _have_ to use /16 mode? It's been many years since I did anything
> with the SCC, but I seem to remember there being /1, /2 and /4 modes also?
> There was some limitation though... they only work for the synchronous
> modes or something?

There are /1, /16, /32, and /64 modes. The problem with the /1 mode is
character synchronization. If we had an external clock common to the
sender and receiver (not just two identical frequency clocks) we might be
able to do /1 mode. But we can't reliably receive with it w/o the external
clock.

In the /16 mode, the chip is able to adjust its bit timing with respect to
the external datastream so that it reads the bits at the middle of the bit
cell.

The /32 and /64 modes are only used when not using the BRG as the BRG can
make those rates and more.

Take care,

Bill