shubbell@pnet02.gryphon.com (Steve Hubbell) (01/20/90)
I am looking for a solution that has plagued the Apple II for as long as I can
remember.
Right now I am working on several projects where it is going to be necessary
to perform disk writes while data is still coming into the serial port.
From my experience with II's over the last six years, I don't believe I have
ever seen this done without character loss.
For the two things I am working on, it is imperative that I not loose
characters when the writes are performed.
If anyone has any suggestions on how this could be performed (either through
software AND/OR hardware) PLEASE give me ANY ideas the come to mind.
-Steve
(By the way, what ever happened to the "hacking" spirit of the Apple
II where nothing was impossible if you just put your mind to it. I still
remember when I would go over to people's houses and see their ][ and ][+'s
with enough wires and modifictions in them to re-wire a major metropolitan
area?? That's what truly made the II a strong computer. People believed in
it and were proud to say "I have a II!")
Just thought I would mention the above. Its something I have been thinking
about a lot lately. I have been looking back at how I saw the II years ago
and how I see it now. It sure has changed....
ANYWAY, if anyone can help me with my interrupt/serial port problem, I would
appreciate it.
Thanks!!
-------------------------------------------------------------------------------
Steve Hubbell - Manhattan Beach, CA
Co-Founder and President Zephyr Technologies
UUCP: {ames!elroy, <backbone>}!gryphon!pnet02!shubbell
INET: shubbell@pnet02.gryphon.com
-------------------------------------------------------------------------------hb@kuling.UUCP (Henrik B}kman) (02/01/90)
My suggestion is to use XON/XOFF flow control to stop the incomming data while doing IO. But then of course, that may be impossible... Good Luck, Erl
dlyons@Apple.COM (David A. Lyons) (02/05/90)
In article <992@rbdc.UUCP> mitch@rbdc.UUCP (Mitch Berry) writes: >well there's all this talk on serial ports .... uhh remember that the iigs >has a "print buffer" that can be turned on for the serial modem port... >which means whether or not the xon/xoff is sent if you have this "print >bufer" on you wont loose data...correct? > >mitch@rbdc The buffering features of the Printer and Modem ports are implemented in firmware, using interrupts to catch incoming characters and store them in RAM until the application is ready to fetch them. Disk access, for many devices, disables interrupts for long enough that you lose some incoming characters--the 8530 serial chip has only a 3-character buffer in the hardware, I believe. -- --David A. Lyons, Apple Computer, Inc. | DAL Systems Apple II Developer Technical Support | P.O. Box 875 America Online: Dave Lyons | Cupertino, CA 95015-0875 GEnie: D.LYONS2 or DAVE.LYONS CompuServe: 72177,3233 Internet/BITNET: dlyons@apple.com UUCP: ...!ames!apple!dlyons My opinions are my own, not Apple's.