11 Mar
2007
11 Mar
'07
6:14 p.m.
> Does it support hardware flow control on the
console port? If not, then
[...]
It doesn't, as-shipped, though I see enough spares
in the the schematic
to implement RTS flow control.
Which owuld presumably be another 'blue wire' mod.
What does the mod consist of? I can't believe
it's really permanent
(although it might well involve soldering to undo it). Losing 38400 buad
is surely not a problem, since few, if any, classic terminals ran at that
speed, and you don't _need_ that sort of data rate for a tectual terminal
anyway.
The baud rate generator is a 4.9152Mhz can oscillator, a 74HC4040
divider, a header and some jumpers. So, the hack is to simply replace the oscillator with a 1.804Mhz one. I've
never seen a
can of that frequency, though, and substituting a 1.8432Mhz
oscillator would leave you about 2% too fast. 3.579Mhz comes
Which would be near enough. I once used a 555 timer as a baud rate
generator, and had no problems at all. Used 1% R's and C's, nearest
standard values to the ones I'd calculated (I forget what they were), and
had no tweeaks. Never had any problems with it.
If the use of the links is the obvious one (that is, to select outputs of
the '4040 and feed it into some more circuitry), you could make an
external PCB with an osiccilator and divider chip on it and connect the
output to the appropriate pin on the jumper block.
-tony