User`s manual

DIGITAL-LOGIC AG MSLB-P5 Manual V0.3
PRELIMINARY 191
16.6.17 Interrupt 17h–EPP Services
Use Interrupt 17h 02h to obtain the BIOS entry point (also called the EPP Vector) to Enhanced Parallel
Printer (EPP) Services. To use the other EPP services, load AH with an appropriate function value and
Far call the EPP Vector.
The following are the EPP exit status codes:
EPP Services Exit Status Codes
AH 00h = No error
01h = Failed I/O function
02h = Invalid function
03h = EPP not supported
04h = Not an EPP port
20h = Multiplexor not present
40h = Multiplexor already locked
The following are the Int 17 EPP services of PhoenixBIOS 4.0:
Interrupt 17h EPP Service
AH = 02h EPP Installation check
Entry:
DX EPP printer port (0-2)
AL 0
CH 45h = "E"
BL 50h = "P"
BH 50h = "P"
Exit:
AL 45h
CX 5050h
DX:BX EPP BIOS entry point
Vectored EPP Services
(Call entry point)
AH = 00h Query EPP port configuration
Entry:
DL EPP printer port (0-2)
Exit:
AL Interrupt level of EPP port (00-15h)
FFh = Interrupts not supported
BH EPP BIOS revision (MMMMnnnn or M.n)
BL I/O capabilities:
Bit 0Multiplexor present
Bit 1PS/2 bi-directional capable
Bit 2Daisy chain present
Bit 3ECP capable
CX SPP I/O base address
ES:DI FAR pointer to EPP BIOS manufacturer's
info/version text string, zero terminated
AH = 01h Set mode
Entry:
DL EPP printer port (0-2)
AL Modes:
Bit 0Set compatibility mode
Bit 1Set Bi-directional mode
Bit 2Set EPP mode
Bit 3Set ECP mode
Bit 4Set EPP software emulation (via
standard parallel port)
AH = 02h Get mode
Entry:
DL EPP printer port (0-2)
Exit:
AL Modes:
Bit 0In compatibility mode
Bit 1In Bi-directional mode
Bit 2In EPP mode
Bit 3In ECP mode
Bit 4In EPP software-emulation mode
Bit 7EPP port interrupts enabled