cs4g6aw@maccs.dcss.mcmaster.ca (Amos Yung) (01/19/90)
Hi, folks!
I am running into trouble again (What else is new?). For some bone-head
reasons, I have to connect a bone-head device that do not output standard
RS-232C signal to the serial port. Moreover, I want the output signal to
trigger a software interrupt. The unfortunate thing is: I really don't
know much about serial port, RS232C, UART.... kinda stuff.
Anybody got any hint? Or can recommend any kind of good sources on such
topics?
I will appreciate any kind of assistance, especially if you can send it to
me via e-mail. A summary will be posted upon request.
Thanks a million in advance. Happy computing!
--
Amos Yung | "Go sit on a PHASER!"
McMaster University|
cs4g6aw@130.113.1.1| - The guy who dressed like Geordi in "Night Court"
|emmo@moncam.co.uk (Dave Emmerson) (01/24/90)
In article <25B62374.8137@maccs.dcss.mcmaster.ca>, cs4g6aw@maccs.dcss.mcmaster.ca (Amos Yung) writes: > Hi, folks! > > I am running into trouble again (What else is new?). For some bone-head > reasons, I have to connect a bone-head device that do not output standard > RS-232C signal to the serial port. Moreover, I want the output signal to > trigger a software interrupt. The unfortunate thing is: I really don't > know much about serial port, RS232C, UART.... kinda stuff. > Without more info it's difficult to tell exactly what your problem is. What kind of output have you got available, what kind of signal does it produce? FYI : RS232c signals are typically +-12volts relative to ground, though the spec allows between +-3V and +-24V. Maxell (amongst others) make a very useful chip, the MAX232 which runs on +5v only, and converts the normal TTL (0-5V) signals used by your PC to/from RS232 level. The alternative, if you have +-12 available is a MC1488, if you don't need to receive from the PC. Don't expect reliable results from a single rail signal. There are lots of UARTS around, but most are micro-controlled, so look for one which can stand-alone. The IM6402IPL can easily be wired to send a preset byte whenever the TBRL pin is waggled, or you may be able to embed some useful info into the transmitted byte. Either way, you can generate an interrupt at the PC. I suggest the 6402, because you can hardwire its pins for baudrate/parity/stop bits, it doesn't need a micro to 'set it up'. All these chips are cheap, common, and well documented. You should be able to get data sheets and parts anywhere in the civilised(?) world. That should be enough to get you started. Dave E.