atkeyboarda51.a51

ps/2键盘处理程序

;========================================================
;
;	ATKeyboard接口函数,CPU外晶振22.1184MHz
;
;========================================================
NAME            ATKEYBOARD_A51

sfr P0    = 0x80;
sfr P1    = 0x90;
sfr P2    = 0xA0;
sfr P3    = 0xB0;
sfr PSW   = 0xD0;
sfr ACC   = 0xE0;

;/*  BIT Registers  */
;  PSW  
sbit CY    = PSW^7;
sbit AC    = PSW^6;
sbit F0    = PSW^5;
sbit RS1   = PSW^4;
sbit RS0   = PSW^3;
sbit OV    = PSW^2;
sbit P     = PSW^0; //8052 only

;**********************************************************
	Virtual_Keyboard_CLK	EQU		P1.1	;虚拟键盘时钟IO
	Virtual_Keyboard_Data	EQU		P1.2	;虚拟键盘数据IO
;**********************************************************
	KEYBOARD_OK				EQU		0		;OK
	KEYBOARD_HOST_BUSY		EQU		1		;主机忙，即有数据发出来
	KEYBOARD_HOST_DISABLE	EQU		2		;主机抑制发送
	KEYBOARD_HOST_WITHDRAW	EQU		3		;主机取消发送
	KEYBOARD_REC_PARITY		EQU		4		;接收校验错
	KEYBOARD_RESENT			EQU		0x0FE	;主机要求重发
;**********************************************************

;**************ATKEYBOARD_A51 function*****************************   
?PR?_ATKeyboard_SendByte?ATKEYBOARD_A51      SEGMENT  CODE
public _ATKeyboard_SendByte
                  
				RSEG    ?PR?_ATKeyboard_SendByte?ATKEYBOARD_A51
;======从模拟键盘口发送单字节=====================
_ATKeyboard_SendByte:
			MOV		A,R7					;保存参数到ACC
			JNB		Virtual_Keyboard_CLK,$	;等待CLK为高电平
			MOV		R7,#44					;延时50us,92T
			CALL	Delay
			JNB		Virtual_Keyboard_CLK,ERR_DISABLE
			JB		Virtual_Keyboard_Data,SEND_StartBit
			LJMP	ReceiveData;DATA为低，有数据下来，直接转去接收
SEND_StartBit:
			CLR		Virtual_Keyboard_Data	;起始位
			CLR		Virtual_Keyboard_CLK
			MOV		R7,#35		;延时40us,74T
			CALL	Delay
			SETB	Virtual_Keyboard_CLK
			MOV		R0,#08		;发送8位数据位,低位在前
SEND_DataBit:
			JNB		Virtual_Keyboard_CLK,ERR_WITHDRAW
			RRC		A
			MOV		Virtual_Keyboard_Data,C
			MOV		R7,#33		;延时40us,74T,减去其它的5T
			CALL	Delay
			CLR		Virtual_Keyboard_CLK
			MOV		R7,#35		;延时40us,74T
			CALL	Delay
			SETB	Virtual_Keyboard_CLK
			DJNZ	R0,SEND_DataBit
SEND_ParityBit:
			JNB		Virtual_Keyboard_CLK,ERR_WITHDRAW
			RRC		A
			MOV		C,P
			CPL		C
			MOV		Virtual_Keyboard_Data,C
			MOV		R7,#32		;延时40us,74T,减去其它的7T
			CALL	Delay
			CLR		Virtual_Keyboard_CLK
			MOV		R7,#35		;延时40us,74T
			CALL	Delay
			SETB	Virtual_Keyboard_CLK
SEND_StopBit:
			JNB		Virtual_Keyboard_CLK,ERR_WITHDRAW
			SETB	Virtual_Keyboard_Data
			MOV		R7,#33		;延时40us,74T,减去其它的4T
			CALL	Delay
			CLR		Virtual_Keyboard_CLK
			MOV		R7,#35		;延时40us,74T
			CALL	Delay
			SETB	Virtual_Keyboard_CLK
			MOV		R7,#35		;延时40us,74T
			CALL	Delay
;接收应答，此处不去接收，直接延时2ms测试结果也没问题
			LJMP	ReceiveEcho	
			;MOV		R7,#00
			;RET
ERR_BUSY:	MOV		R7,#KEYBOARD_HOST_BUSY;主机忙
			RET
ERR_DISABLE:MOV		R7,#KEYBOARD_HOST_DISABLE;主机抑制发送
			RET
ERR_WITHDRAW:MOV	R7,#KEYBOARD_HOST_DISABLE;主机取消发送
			RET
ERR_RESENT:	MOV		R7,#KEYBOARD_RESENT;主机要求重发
			RET

;==================接收应答========================
?PR?ReceiveEcho?ATKEYBOARD_A51      SEGMENT  CODE
public ReceiveEcho
				RSEG    ?PR?ReceiveEcho?ATKEYBOARD_A51
ReceiveEcho:
			MOV		R0,#150		;等待1.5ms
			MOV		R1,#00		;CLK低电平时长累计
Wait_Data:	MOV		R7,#07		;延时10us,18T
			CALL	Delay
			JB		Virtual_Keyboard_CLK,CheckTime
TotalTime:	INC		R1			;累计CLK低电平时长
			MOV		A,#10
			CLR		C
			SUBB	A,R1		;判断CLK低电平时长
			JC		ReceiveData	;超过90us认为PC机有数据下来
CheckTime:	DJNZ	R0,Wait_Data;
			CLR		A
			LJMP	ReceiveOK;没收到应答
ReceiveData:JNB		Virtual_Keyboard_CLK,$	;等待CLK高电平
			MOV		R7,#02		;延时5us,9T
			CALL	Delay
			CLR		A
			JB		Virtual_Keyboard_Data,ReceiveOK;DATA为高电平，说明主机放弃发送
;收到起始信号后，必须在20ms内给出时钟，这里按40us来给
;另收数据时，在低电平时，PC机交换数据，高电平时可以读数据
			MOV		R7,#07		;延时10us,18T
			CALL	Delay
			JB		Virtual_Keyboard_Data,ReceiveOK;DATA为高电平，说明主机放弃发送
			CLR		Virtual_Keyboard_CLK
			MOV		R0,#09		;接收8位数据和1位校验
ReceiveBit:	MOV		R7,#35		;延时40us,74T
			CALL	Delay
			SETB	Virtual_Keyboard_CLK
			MOV		R7,#16		;延时20us,36T
			RRC		A
			MOV		C,Virtual_Keyboard_Data
			CALL	Delay
			MOV		R7,#16		;延时20us,36T
			CALL	Delay
			CLR		Virtual_Keyboard_CLK
			DJNZ	R0,ReceiveBit	;判断是否接收完毕
Rec_Stopbit:MOV		R7,#35		;延时40us,74T
			CALL	Delay
			SETB	Virtual_Keyboard_CLK
;之后每10us检查一次CLK，若为低，则表示PC放弃发送，则重新等待接收
			JNB		Virtual_Keyboard_CLK,ReceiveEcho;CLK为低电平，说明主机放弃发送
			MOV		R7,#07		;延时10us,18T
			CALL	Delay
			JNB		Virtual_Keyboard_CLK,ReceiveEcho;CLK为低电平，说明主机放弃发送
			JNB		Virtual_Keyboard_Data,ReceiveEcho;DATA为低电平，说明主机放弃发送
			MOV		R7,#07		;延时10us,18T
			CALL	Delay
			JNB		Virtual_Keyboard_CLK,ReceiveEcho;CLK为低电平，说明主机放弃发送
			JNB		Virtual_Keyboard_Data,ReceiveEcho;DATA为低电平，说明主机放弃发送
			MOV		R7,#07		;延时10us,18T
			CALL	Delay
			JNB		Virtual_Keyboard_CLK,ReceiveEcho;CLK为低电平，说明主机放弃发送
			JNB		Virtual_Keyboard_Data,ReceiveEcho;DATA为低电平，说明主机放弃发送
Send_ACK:	CLR		Virtual_Keyboard_Data
			MOV		R7,#02		;延时5us,9T
			CALL	Delay
			CLR		Virtual_Keyboard_CLK
			MOV		R7,#35		;延时40us,74T
			CALL	Delay
			SETB	Virtual_Keyboard_CLK
			MOV		R7,#02		;延时5us,9T
			CALL	Delay
			SETB	Virtual_Keyboard_Data
Check_Parity:
			JB		P,Check1
			JNC		ERR_Receive
			SJMP	ReceiveOK
Check1:		JC		ERR_Receive
			SJMP	ReceiveOK
ERR_Receive:MOV		R7,KEYBOARD_REC_PARITY
			RET
ReceiveOK:	MOV		R7,A	;接收到的值存于ACC中
			RET

;=====延时函数=================
?PR?Delay?ATKEYBOARD_A51      SEGMENT  CODE
public Delay
				RSEG    ?PR?Delay?ATKEYBOARD_A51
Delay:		DJNZ	R7,$
			RET

			END