Technical information

Using NewBIOS Serial Solutions

DX := $1; {COM2}

Intr($14, Ioregs); {Asynchronous services}

( AH AND $80 ) <> 0 {Check that send ok}

THEN

Writeln(’COM2 timed out on output.’);

END;

END.

Example 3, Setting Port Addresses.______________________________

I/O addresses for COM3 and COM4 are set using service

ADH. This is a service available only to NewBIOS. The

program also checks for the presence of NewBIOS.

USES

DOS; {Contains Registers type and Intr Procedure}

VAR

Ioregs: Registers;

Com3Addr,

Com4Addr: Word;

BEGIN

{Pascal code fragment to set}

(COM3 and COM4 addresses.}

WITH Ioregs DO BEGIN

Com3Addr := $3220;

Com4Addr := $3228;

AH := $AD; {Service ADH, set address}

DX := $2; {COM3}

BX := Com3Addr; {Address of COM3}

Intr($14, Ioregs); {Asynchronous services}

AX <> $52AD {Check NewBIOS present}

THEN BEGIN

Writeln(’NewBIOS not installed!’);

Halt(1);

END;

AH := $AD; {Service ADH}

DX := $3; {COM4}

BX := Com4Addr; {Address of COM4}

Intr($14, Ioregs);

END;

Chapter 4 Page 55