mm3d+@andrew.cmu.edu (Matt McNally) (10/24/89)
Does anyone have any experience with sending an actual 'Break' through the serial ports? Although IM-II defines a 'Break' as when "the line is held in the 'space' state for one frame or longer", I have yet to discover exactly how I can acomplish this feat. Any help would be extremely appreciated. Matt =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-= 'Macintosh II Project' Research Programmer/Dugan Carnegie Mellon, H&SS Dean's Office, Pittsburgh, PA 15213 Office: Baker Hall 369-B, (412) 268-6990 ARPANET Address: mm3d@andrew.cmu.edu =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-= For those who are interested, here's why... We have built a really simple router that allows us to 'focus' the serial line to any of eight devices. But in order to set the 'focus' mask I need to send a 'Break' to the router to let it know I'm changing the focus instead of actually sending a data character through. Although we could use the serial drivers 'break mode' by changing the hardware, we would really like to use a 'Break' as this keeps the hardware down to a bare minimum.
han@apple.COM (Byron Han, Project Scapegoat) (10/24/89)
In article <8ZErPKm00UhWM2olYY@andrew.cmu.edu> mm3d+@andrew.cmu.edu (Matt McNally) writes: > Does anyone have any experience with sending an actual > 'Break' through the serial ports? Although IM-II defines > a 'Break' as when "the line is held in the 'space' state > for one frame or longer", I have yet to discover exactly > how I can acomplish this feat. > Inside Macintosh II-252/253 SerSetBrk and SerClrBrk descibes routines to cause breaks to occur on the serial drivers/ports. +-------------------------------------------------------------------------- ---+ | Disclaimer: Apple has no connection with my postings. | +-------------------------------------------------------------------------- ---+ Byron Han, CommToolbox Scapegoat "DeAnza 3 - R.I.P. - 10/17/89 5:04PM" Apple Computer, Inc. ----------------------------------------- 20525 Mariani Ave, MS 27Y Internet: han@apple.COM Cupertino, CA 95014 UUCP:{sun,voder,nsc,decwrl}!apple!han ------------------------------------ GENIE:BYRONHAN CompuServe:72167,1664 ATTnet: 408-974-6450 Applelink:HAN1 HAN1@applelink.apple.COM --------------------------------------------------------------------------- ---
mm3d+@andrew.cmu.edu (Matt McNally) (10/25/89)
Many thanks for the replies. It turns out that I was correctly sending a 'Break' using the SerSetBrk and SerClrBrk functions, (which was the most common reply to my initial query), but that our hardware 'box' wasn't responding correctly. After re-reading IM-II when the initial commands seemed to fail I wasn't sure what Apple meant by 'break mode', but with your replies my 'case' for rechecking the hardware was much stronger. Again, many many thanks. As for some of your other suggestions, which included various methods for generating framing errors, although I didn't try any of them, I am once again amazed at the ingenuity of Macintosh programmers. It must be a result of trying program a machine with a 'floating' OS...:-). Matt McNally =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-= Matt McNally - 'Macintosh II Initiative' Research Programmer/Dugan Carnegie Mellon, H&SS Dean's Office, Pittsburgh, PA 15213 Office: Baker Hall 369-B, (412) 268-6990 ARPANET Address: mm3d@andrew.cmu.edu < No disclaimer! > =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=