aw@grpthry.UUCP (Alan Whitton) (07/02/86)
Hello,
I have just noticed that Radio Shack has finally brought the price of the
Colour Computer's 0 drive down to a reasonable level, but now I am wondering if
it is worth buying it at all. The video interface to the CoCo really is not
what I want, though I would not mind keeping it for its graphics abilities.
My question is this: is it possible to somehow connect a plain alphanumeric
terminal to the CoCo II in any way? I would guess that OS-9 would make it easier
but I would like to hear from anyone who would have even a guess as to whether
this was possible. It seems another serial port is needed, but how would this
be done?
{ Place your message here }
alanjimomura@lsuc.UUCP (Jim Omura) (07/05/86)
In article <163@grpthry.UUCP> aw@grpthry.UUCP (Alan Whitton) writes: >Hello, > >I have just noticed that Radio Shack has finally brought the price of the >Colour Computer's 0 drive down to a reasonable level, but now I am wondering if >it is worth buying it at all. The video interface to the CoCo really is not It depends. Better drives (double sided) can be bought fairly cheaply and you can buy a 2nd source controller and case and power supply and make a much better drive system, but it'll cost more overall and servicing is a problem. This is generally better for experienced hardware hackers. >what I want, though I would not mind keeping it for its graphics abilities. > >My question is this: is it possible to somehow connect a plain alphanumeric >terminal to the CoCo II in any way? I would guess that OS-9 would make it easier >but I would like to hear from anyone who would have even a guess as to whether >this was possible. It seems another serial port is needed, but how would this >be done? It can be done either through the bit-banger port or the RS-232 Pak. I'd prefer to use the RS-232 pak myself because it reduces processor overhead and therefore speeds up your system a bit. If you use the bit-banger port, you can still have printout capability by attaching your printer to the terminal (on at least some terminals). Cheers! -- Jim O. -- James Omura, Barrister & Solicitor, Toronto ihnp4!utzoo!lsuc!jimomura Byte Information eXchange: jimomura (416) 652-3880
pritch@osu-eddie.UUCP (Norman Pritchett) (07/09/86)
In article <163@grpthry.UUCP> aw@grpthry.UUCP (Alan Whitton) writes: +--------------- |My question is this: is it possible to somehow connect a plain alphanumeric |terminal to the CoCo II in any way? I would guess that OS-9 would make it |easier but I would like to hear from anyone who would have even a guess as |to whether this was possible. It seems another serial port is needed, but |how would this be done? +--------------- I won't say its *IMPOSSIBLE* to do with RS-DOS but I wouldn't even consider it if I weren't the author of RS-DOS. RS-DOS and the TV/Keyboard are tied too closely together. When you are running OS-9 its trivial. I've been using a VT100-compatible terminal with my CoCo for almost a year now and its been great. The builtin serial port is sufficient (although better performance may be achieved through the Deluxe RS-232 pack and version 2 of OS-9). Make a DIN to DB25 connector thus: DIN DB25 --- ---- xmt data RD (pin 3) rcv data TD (pin 2) signal ground GND (pin 7) carrier detect DCD (pin 8) Sorry, I don't remember the signal assignments on the DIN plug. Depending on the terminal you might need to use RTS(pin 4) or DSR(pin 6) instead of DCD(pin 8). Now, any of the following commands under OS-9 will start a process under the control of the serial port (which is called /T1 when not being used with printer): shell >/t1 </t1 >>/t1 * to pass control to the terminal shell >/t1 </t1 >>/t1 & * to still have control at the keyboard tsmon /t1 * to require users to login If you know Unix this probably looks familiar -- no? ">>" redirects stderr instead of appending stdout. SHELL is the name of the shell rather than "sh" or "csh". TSMON is the equivalent of "getty" I presume. Unfortunately, the device driver that Radio Shack wrote for /T1 will only read characters reliably up to 300 or 600 baud. Above that, input gets severly garbled. I believe this is because the driver continuously must poll the receive data line and it can only do it so fast before trashing the response time of the whole machine (or the rest of the machine trashing the response time of the driver). Fortunately, in the May 1984 (1985?) issue of Rainbow Magazine a user submitted an interrupt-driven version of the RS232 driver which requires the user to tie the reeive data pin to the data carrier detect pin and takes advantage of the the carrier detect pin's ability to generate interrupts (I won't go into more detail than that, read the article). This lets you go all the way up to 19200 baud through that silly bit-banger port and it works!!! There is occasional garbage at 19200 so I use 9600. -- Norm Pritchett, The Ohio State University BITNET: TS1703 at OHSTVMA Bellnet: (614) 422-0885 UUCP: cbosgd!osu-eddie!pritch CSNET: pritch@ohio-state ARPANET: NPRITCHETT%osu-20@ohio-state (or) pritch@ohio-state