DOS ain't dead

uart interrupt tx rx in Dos32 bit open watcom (Developers)

posted by Brian_extended, 05.01.2014, 20:42

> > Is there a way to upload a 30KByte file on this site?
>
> Probably not good idea, try http://pastebin.com/ and post link
> here :)

I ended up bypassing the BIOS calls for screen output and keyboard input to reduce the number of mode switches between protected mode and real mode. The mode switches were taking up a lot of time, and interrupts were getting lost. Wrote a couple of routines to access screen memory directly and the keyboard FIFO in real mode. At this point, I have interrupt driven RX and TX, all to some larger queues and working with the 16550. If there is interest, send me a PM with an Email address and i will provide the code.

The code is working on several machines, but not the WINsystems PPM800 PC104 board- they have some extra features that allow multiple com ports to share one interrupt. They left out some steps in the documentation, "am in pursuit" of it. ST240 does not work on their board, either- so it's them, not me.

Phar Lap maps the 1MByte real-mode memory as Segment 34h. Makes it easy to access real-mode memory while in protected mode.

Complete thread:

• uart interrupt tx rx in Dos32 bit open watcom - maui, 11.11.2013, 11:14 (Developers)
  • uart interrupt tx rx in Dos32 bit open watcom - RayeR, 11.11.2013, 19:34
    • uart interrupt tx rx in Dos32 bit open watcom - RayeR, 12.11.2013, 01:50
  • uart interrupt tx rx in Dos32 bit open watcom - tom, 12.11.2013, 12:24
    • uart interrupt tx rx in Dos32 bit open watcom - RayeR, 12.11.2013, 12:30
    • uart interrupt tx rx in Dos32 bit open watcom - bretjohn, 12.11.2013, 16:55
      • uart interrupt tx rx in Dos32 bit open watcom - maui, 12.11.2013, 19:23
        • uart interrupt tx rx in Dos32 bit open watcom - bretjohn, 12.11.2013, 21:12
        • uart interrupt tx rx in Dos32 bit open watcom - tom, 13.11.2013, 11:22
          • uart interrupt tx rx in Dos32 bit open watcom - maui, 13.11.2013, 15:49
            • uart interrupt tx rx in Dos32 bit open watcom - Oso2k, 13.11.2013, 22:26
              • uart interrupt tx rx in Dos32 bit open watcom - maui, 15.11.2013, 19:43
                • uart interrupt tx rx in Dos32 bit open watcom - tom, 16.11.2013, 19:02
                  • uart interrupt tx rx in Dos32 bit open watcom - Brian_extended, 17.11.2013, 04:21
                    • uart interrupt tx rx in Dos32 bit open watcom - maui, 19.11.2013, 12:42
                      • uart interrupt tx rx in Dos32 bit open watcom - Brian_extended, 19.11.2013, 20:59
                      • uart interrupt tx rx in Dos32 bit open watcom - Brian_extended, 22.11.2013, 15:22
                        • uart interrupt tx rx in Dos32 bit open watcom - Brian_extended, 23.11.2013, 03:09
                          • uart interrupt tx rx in Dos32 bit open watcom - maui, 24.11.2013, 13:45
                            • uart interrupt tx rx in Dos32 bit open watcom - Brian_extended, 26.11.2013, 23:25
                              • uart interrupt tx rx in Dos32 bit open watcom - RayeR, 27.11.2013, 03:26
                                • uart interrupt tx rx in Dos32 bit open watcom - Brian_extended, 05.01.2014, 20:42
                                  • uart interrupt tx rx in Dos32 bit open watcom - Brian_extended, 26.01.2014, 02:06
                                    • uart interrupt tx rx in Dos32 bit open watcom - tom, 27.01.2014, 22:46
  • uart interrupt tx rx in Dos32 bit open watcom - Brian_extended, 16.11.2013, 01:14
    • uart interrupt tx rx in Dos32 bit open watcom - Brian_extended, 16.11.2013, 01:15
    • uart interrupt tx rx in Dos32 bit open watcom - Brian_extended, 16.11.2013, 01:16
  • uart interrupt tx rx in Dos32 bit open watcom - Brian_extended, 16.11.2013, 01:32