[net.micro.6809] Using /t1 on CoCo

sdyer@bbncca.ARPA (Steve Dyer) (01/15/84)

I haven't been able to use /t1 with my H19 terminal faster than 300 baud
without garbaging input and/or output.  Any clues?
-- 
/Steve Dyer
decvax!bbncca!sdyer
sdyer@bbncca

riber@uicsl.UUCP (01/17/84)

#R:bbncca:-47800:uicsl:21600007:000:513
uicsl!riber    Jan 16 10:48:00 1984


	I can use 600 baud on my DEC terminal, but mostly suffer your
same problem. The problem seems to be getting the coco to poll the
rs232 line properly. I can print to my terminal at 2400 baud most of the
time - it just won't send.
 	It would be nice to work 9600 baud, but I think the soft rs232
port will just have to go if you want any realistic speed.

	Has anyone done anything with RS's new rs232 plug on???
Does it work? Is there a driver available for it?

					Rick Berry
					pur-ee!uiucdcs!uicsl!riber

danm@mspiggy (Dan McCabe) (01/18/84)

It has been suggested at one of the meetings of a Motorola User's Group
which I attend that you can run at 9600 baud by using the fourth line
(the others are Signal Ground, Transmit Data, and Receive Data) to interrupt
the processor when data is received.  Radio Shack calls this line their
Carrier Detect line, which is normally generated by modems when the
carrier is detected (makes sense).  However, this line is connected to
one of the interruptable inputs of one of the PIA's in the CoCo.  With
proper signal conditioning (convert RS-232 levels to TTL), the Recieve Data
line could be connected to this line and interrupt the processor when
the start bit is recieved.

Of course, this means that you will need to write a new RS232 module, as
well as design some hardware (however minimal).

					Happy hacking,
					Dan McCabe
					decvax!microsoft!danm

Disclaimer:  I haven't tried this method, so try it at your own risk.
However, it does sound like a reasonable technique;  if it wasn't, I wouldn't
have suggested it.