time constarint a clock generated by a counter

Generated clocks are usually considered bad practice.

Why not try using a clock enable

something like

baud : process(clock)

begin

...

if (clock'event and clock = '1') then

if (count = finalCount) then

count <= 0;

clockEnable <= '1';

else

count <= count + 1;

clockEnable <= '0';

end if;

end if;

end process baud;

other_stuff : process(clock)

begin

...

if (clock'event and clock = '1') then

if (clockEnable = '1') then

do stuff

end if;

end if;

end process other_stuff;

Everything is driven from the one clock but the logic in the second process is controlled by a clock enable signal from the baud rate process.

Hope this is of some help