delphi 中没有 但可以嵌入汇编.
程序不是我写的,但已都测试通过.希望对你有帮助//-------------------------------------
{*
* Port Read byte function
*Parameter:port address
*Return: byte value from given port
*}
function PortReadByte(Addr:Word) : Byte; StdCall //assembler; register;
var Pbyte:Byte;
begin
asm
Mov DX,Addr
IN AL,DX
Mov Pbyte,AL
end;
Result:=Pbyte;
end;
{*
* HIGH SPEED Port Read Word function
* Parameter: port address
* Return: word value from given port
* Comment:may problem with some cards and computers that
can't to access whole word, usualy it works.
*}
function PortReadWord(Addr:Word) : Word;StdCall; //assembler; register;
var PWord:Word;
begin
asm
MOV DX,Addr
IN AX,DX
Mov PWord,Ax
end;
Result:=PWord;
end;
{*
* LOW SPEED Port Read Word function
* Parameter: port address
*Return:word value from given port
*Comment:work in cases,only to adjust DELAY if need
*}
function PortReadWordLS(Addr:Word):Word; Stdcall;//assembler; register;
Const Delay = 150;
var PWord:Word;
begin
asm
MOV DX,Addr
IN AL,DX
//read LSB port
MOV ECX,Delay
@1:
LOOP @1 //delay between two reads
XCHG AH,AL
INC DX
//port+1
IN AL,DX //read MSB port
XCHG AH,AL //restore bytes order
Mov Pword,Ax
end;
Result:=Pword;
end;
{* Port Write byte function*}
procedure PortWriteByte(Addr:Word; Value:Byte);Stdcall;// assembler; register;
begin
asm
MOV DX,Addr//XCHG AX,DX
MOV AL,Value
OUT DX,AL //OUT DX,AL
end;
end;
{*
* HIGH SPEED Port Write word procedure
* Comment:may problem with some cards and computers that
can't to access whole word, usualy it works.
*}
procedure PortWriteWord(Addr:word; Value:word); Stdcall;//assembler; register;
begin
asm
Mov DX,Addr //XCHG AX,DX
Mov AX,Value
OUT DX,AX
end;
end;
{*
* LOW SPEED Port Write Word procedure
*}
procedure PortWriteWordLS(Addr:word; Value:word);Stdcall;// assembler; register;
const Delay = 150;
begin
asm
//XCHG AX,DX
Mov DX,Addr
Mov AX,Value
OUT DX,AL
MOV ECX,Delay
@1:
LOOP @1
XCHG AH,AL
INC DX
OUT DX,AL
end;
End; //------------------------------------------
程序不是我写的,但已都测试通过.希望对你有帮助//-------------------------------------
{*
* Port Read byte function
*Parameter:port address
*Return: byte value from given port
*}
function PortReadByte(Addr:Word) : Byte; StdCall //assembler; register;
var Pbyte:Byte;
begin
asm
Mov DX,Addr
IN AL,DX
Mov Pbyte,AL
end;
Result:=Pbyte;
end;
{*
* HIGH SPEED Port Read Word function
* Parameter: port address
* Return: word value from given port
* Comment:may problem with some cards and computers that
can't to access whole word, usualy it works.
*}
function PortReadWord(Addr:Word) : Word;StdCall; //assembler; register;
var PWord:Word;
begin
asm
MOV DX,Addr
IN AX,DX
Mov PWord,Ax
end;
Result:=PWord;
end;
{*
* LOW SPEED Port Read Word function
* Parameter: port address
*Return:word value from given port
*Comment:work in cases,only to adjust DELAY if need
*}
function PortReadWordLS(Addr:Word):Word; Stdcall;//assembler; register;
Const Delay = 150;
var PWord:Word;
begin
asm
MOV DX,Addr
IN AL,DX
//read LSB port
MOV ECX,Delay
@1:
LOOP @1 //delay between two reads
XCHG AH,AL
INC DX
//port+1
IN AL,DX //read MSB port
XCHG AH,AL //restore bytes order
Mov Pword,Ax
end;
Result:=Pword;
end;
{* Port Write byte function*}
procedure PortWriteByte(Addr:Word; Value:Byte);Stdcall;// assembler; register;
begin
asm
MOV DX,Addr//XCHG AX,DX
MOV AL,Value
OUT DX,AL //OUT DX,AL
end;
end;
{*
* HIGH SPEED Port Write word procedure
* Comment:may problem with some cards and computers that
can't to access whole word, usualy it works.
*}
procedure PortWriteWord(Addr:word; Value:word); Stdcall;//assembler; register;
begin
asm
Mov DX,Addr //XCHG AX,DX
Mov AX,Value
OUT DX,AX
end;
end;
{*
* LOW SPEED Port Write Word procedure
*}
procedure PortWriteWordLS(Addr:word; Value:word);Stdcall;// assembler; register;
const Delay = 150;
begin
asm
//XCHG AX,DX
Mov DX,Addr
Mov AX,Value
OUT DX,AL
MOV ECX,Delay
@1:
LOOP @1
XCHG AH,AL
INC DX
OUT DX,AL
end;
End; //------------------------------------------
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2。用控件spcomm
3。用API CreateFile()等
4。调用现成的 .DLL
如果你使用的是win2k/nt,直接读写端口的意义不大,因为很多端口系统是禁止读写的,
如果使用的是win9x,则可以使用Delphi的嵌入式汇编,很简单:
asm
mov al,$01
out $61,al
in al,$61
end;