[Coco] Max baud rate for 68681 in MM/1?

[Joel Ewy]

I read ambiguous information about the 68681 on the MM/1's I/O board.  
Does anybody have a definitive word?  Page 2-5 of the MM/1 technical 
manual claims that it can be run at "1 megabytes per second" (seriously 
8M bits/sec?), but the table on page 9-2 and the text on 9-2 state that 
the maximum baud rate is 34,800.  Is this a pragmatic maximum based on 
the CPU's ability to service the DUART's on-chip buffers without 
interrupt-masking trickery, is it the real hard maximum for the 68681, 
or is it a hard maximum imposed by the MM/1's hardware?  Anybody have 
any insight?

JCE