>I know that at least two 8530 uarts can speak with each other at baudrate
>generator value 0 (from a target hardware which even has the same quartz).

I had intended to limit it to 1 (allowing 51200 baud), but for some
reason my original driver code had `2' instead (38400 baud).  I
just re-checked the hardware documentation, and it sort of vaguely
hints that zero might work (it says the output of the BRG `toggles'
when the count `reaches zero', which is unclear since with TC=0
the counter never `reaches zero' -- it simply `stays zero' -- but
the output `toggles' rather than `pulses').

But yes, after 38400 the only speeds available are 51200 and 76800,
at least with a x16 clock (you could go to a x1 clock but then you
risk inaccurate sampling).

Chris