[comp.sys.ibm.pc] IBM-AT Interrupt lines and their uses?

mdf@osu-eddie.UUCP (Mark D. Freeman) (05/05/87)

I need a list of all the interrupt lines on an IBM-AT and what devices
usually use those lines.  I have two boards that usually live on IRQ5,
and both need to be in the same system.  Both can be moved to other
IRQs, but I have no idea which other IRQs are available for use.

Can anyone help?


-- 
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Mark D. Freeman						    mdf@osu-eddie.uucp
StrongPoint Systems, Inc.				   mdf@Ohio-State.arpa
2440 Medary Avenue				      ...!cbosgd!osu-eddie!mdf
Columbus, OH  43202		    Guest account at The Ohio State University
(614) 262-3703
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mason@tc.fluke.COM (Nick Mason) (05/08/87)

In article <3494@osu-eddie.UUCP> mdf@osu-eddie.UUCP (Mark D. Freeman) writes:
>I need a list of all the interrupt lines on an IBM-AT and what devices
>usually use those lines.  I have two boards that usually live on IRQ5,

  Here is a list of I/O address and Hardware interrupt lines:

     
     Address (HEX)       Device
     000-0FF             Internal I/O
     000-01F             DMA (8237A-5)
     020-03F             Interrupt controller(8259A)
     040-043             System Timer (8253-5)
     040-05F    AT       timer (8254)
     060-063             PPI Status (8255A-5)
     060-06F    AT       8042 (Keyboard)
     070-07F    AT       real-time clock, NMI mask
     080-083             DMA Page Registers
     080-09F    AT       DMA page registers (74612)
     0A0-0AF             NMI Registers
     0A0-0BF    AT       Int controller #2 (8259A)
     0C0-0C0             Diagnostic LED's (Zenith)
     0C1-0CF             Reserved
     0C0-0DF    AT       DMA controller #2
     0E0-0E3             68A21 Parallel
     0E4-0EF             Reserved
     0F0-0FF    AT       Math Coprocessor
     1F0-1F8    AT       Fixed Disk
     200-20F             Game I/O
     210-217             Expansion Unit
     220-24F             Reserved
     278-27F             LPT2:
     2F0-2F7             Reserved
     2F8-2FF             COM2:
     300-31F             Prototype Card
     320-32F             Hard Disk (#1 @ 320; #2 @ 322)
     360-36F             reserved
     378-37F             LPT1 (Printer)
     380-38C             SDLC comm.
     390-399             Binary comm. 2
     3A0-3A9             Binary comm. 1
     3B0-3BF             Monochrome card or LPT2  (3BC-3BE)
     3C0-3CF             Reserved
     3D0-3DF             Color Graphics card
     3E0-3E7             Reserved
     3F0-3F7             Floppy Disk (3F2-3F5)
     3F8-3FF             COM1:
 
 
  INT 8 thru 0FH - Vectored Hardware Lines (in IBM at least)
     In IBM, these 8 interrupts are generated in
  response to IRQ 0 through IRQ 7 (if enabled via port 21).
        IRQ0           Timer interrupt
        IRQ1           Keyboard interrupt
        IRQ2           expansion board
        IRQ3           COM2
        IRQ4           COM1
        IRQ5           hard disk
        IRQ6           floppy disk
        IRQ7           printer
 
   On the AT, IRQ2 is chained to a second 8259 with the following:
        IRQ8           Realtime clock
        IRQ9           software redirected to IRQ2
        IRQA           reserved
        IRQB           reserved
        IRQC           reserved
        IRQD           coprocessor
        IRQE           Fixed disk controller
        IRQF           reserved
 
 
Nick Mason