Bios System Service-parallel port service

7 parallel port service (parallel port service -- int 17 h)

00 h-output characters to the printer

01 H-initialize the printer port

02 h-read printer status

 

(1) function 00 h

 

Function Description: output characters to the printer

Entry parameter: Ah = 00 h

Al = output character

DX = printer No. (0-lpt1, 1-lpt2, 2-lpt3 ,......)

Exit parameter: Ah = printer status. When the value is 1, the meaning is as follows: Bit 7-printer idle bit 3-I/o Error

6-printer response 2-Reserved

Bit 5-no paper bit 1-retained

4-printer selected 0-printer time-out

 

(2) function 01 H

 

Function Description: Initialize the printer port.

Entry parameter: Ah = 01 H

DX = printer No. (0-lpt1, 1-lpt2, 2-lpt3 ,......)

Exit parameter: Ah = printer status. You can define the following functions for H.

 

(3) function 02 h

 

Function Description: Read the printer status.

Entry parameter: Ah = 02 h

DX = printer No. (0-lpt1, 1-lpt2, 2-lpt3 ,......)

Exit parameter: Ah = printer status. You can define the following functions for H.