8086 int 17h Printer Interrupt



8086 int 17h Printer Interrupt


The INT 17 software interrupt supports up to 4 parallel adapters. The BIOS stores the standard base addresses for three parallel adapters in the BIOS Data Area at 3FCh, 378h, and 278h. These services use the I/O ports 0278h-027Ah, 0378h-037Ah, and 03BCh-03BEh.

Function 00h Print character


Input:
       AL Character to print
       DX Printer port (0-3)
Output:
         AH Printer Status

Function 01h Initialize printer port


Input:
       DX Printer port (0-3)
Output:
       AH Printer Status

Function 02h Return printer status


Input:
        DX Printer port (0-3)
Output:
        AH Printer Status:
        Bit 0 1 = Time-out error
        Bit 1 Reserved
        Bit 2 Reserved
        Bit 3 1 = I/O error
        Bit 4 1 = Printer selected
        Bit 5 1 = Out of paper
        Bit 6 1 = Acknowledgment from printer
        Bit 7 1 = Printer not busy