DOS ain't dead

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

posted by Brian_extended, 22.11.2013, 15:22

The fun of staying up late last night and debugging code...

I found that checking the Interrupt ID register of the serial port in the Handler "did not work as well as it did decades ago"... I'm used to reading this register at the beginning of the handler and checking the conditions individually.

Changed Strategy: Using the Line Status Register to check the Receive Buffer Ready and Transmit buffer empty no matter WHAT condition causes the interrupt works. Checking the Interrupt ID register: highest priority sets it, and a lower priority interrupt coming in while in the handler was lost.

Turns out I started a protected mode interrupt handler in 1994 for Phar Lap. I could not find any of my code that actually used it. I stuck with real-mode for the RS232, and switched to a different interface for protected mode. TWENTY years later, "comio386.asm" is working. New version using circular queues for both TX and RX coming up. I need this thing to work for a new piece of hardware.

Complete thread:

• uart interrupt tx rx in Dos32 bit open watcom - maui, 11.11.2013, 11:14
  • 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