一个PS/2仿真键盘的设计
设计目的：
１．熟悉PS/2协议的原理
２．学习单片机的使用
设计内容：
依照PS/2协议，在51芯片上开发汇编程序，使得按下开发板上的按键时，能够在PC机上输出a、b、c。
实验环境：
开发板、STC12C2052AD芯片、PS/2线、PC机、Keil软件、STC-ISP程序下载器
相关参数：
单片机振荡频率6MHz（具体情况请看此型号单片机用户手册）
指令周期0.5微秒（51型单片机的指令周期是其振荡频率的12分之一）
PS/2连接器引脚定义（见参考文献《PS/2技术参考》）
能够接受的键盘时钟信号频率10-20KHz（最大33KHz，推荐设为15KHz）
设计思想：
使用开发板上的按钮产生中断信号，使单片机进入相应的中断处理程序，从而向PC机发送相应的扫描码。PC机主板中有一个解码芯片，此芯片在收到扫描码之后，引发PC机操作系统的中断（I/O的中断），转到操作系统中的中断处理程序，从面在系统中输出相应字符。
原理：
实际的通用键盘上的每一个键都对应一个唯一个扫描码，这些键会在极短的时间内被扫描一遍，以确认它们有没有被按下，如果某个键被按下了，就发送其相应的扫描码。而在开发板上，51芯片有三个按键，对应芯片上的两个中断口和一个定时／计数器输入口。中断接口可以直接使用，当按下键时就触发中断，而定时／计数器需要设置为初始值为FFH，一旦按下键便会溢出而产生中断的计数器。
主机与键盘有四根线相连，时钟信号数、数据线、接地线、电源线。
时钟信号在任何时刻都是由键盘产生的，PC机在时种的下降沿接收数据线上的信号，要是PC机向键盘发送数据，则键盘在时钟的上升沿接收数据线上的数据。虽是由键盘产生时钟信号，但是PC机对总线有着绝对的控制权，只要其将时钟线拉低（高低电平信号有这样的特性：只有一端的信号为低电平，则整条线的信号都为低电平。这就是为什么要向单片机I/O口输出一个信号，要先将外部输入单片机这个I/O口的信号释放（拉高）。否则输出的永远都是低电平），就要以抵制键盘的输出。
总线上有这些几种状态：
１、PC等待键盘输出状态（键盘可以输出状态）：CLK=1,DATA=1;
２、键盘等待PC输出状态（PC可以输出状态）：CLK=1,DATA=0（这个状态之前还有一些状态要生产生的，详情请见参考文献《PS/2技术参考》）
３、正在输出状态：此时的时钟线与数据线上的信号没有定值，依据所要发送的数据不同而不同，CLK=X,DATA=X
键盘从外部存储器中读取相应键位的扫描码，当要改变某个键所要发送的扫描码时，只需改变外部存储器中对应位置的扫描码，这样就可以方便地改变某键所要发送的扫描码。在存放扫描码时，只需将扫描码按顺序存放，如E0,70按存储地址从小到大顺序地排列。因为通码（make code）最多只有两个十六进制数，且如有两个则第一个必是E0H，而断码（break code）最多只有三个，且如果有三个，则第一个必是E0H,如果有二个，则第一个必是F0H。所以，当发送时，如果发现第一个是E0H或F0H的话，则再发送其后的一个扫描码。
注意事项：
１、 发送8个数据位时，是低位先发送（least significant bit first），如果是用高位先发送，主机自然是无法识别会发送的数据，会报警；
２、 如果想要精确计算时间，那么像子程序调用语句会占用两个指令周期也应该考虑到；
３、 连接线应该连在指示灯靠近51芯片的一端，否则无法接收到主机发来的信号；PS/2
４、 汇编程序前的org 语句必须按其指示的地址大小排列，小的在前，大的在后；
程序：
;
=======================================
; program
; check clk and data before every 8 bit data sending
; a function is created for send all 11bit data
; a function is created for parity calculating
; CAPSLOCK :BIG LETTER P1.3=0,SMALL LETTER P1.3=1
; =======================================
; =======================================
; VARS USED LOCALY
; R0 IS USED LOCALY AS A COUNTER
; 20H.1 20H.2 20H.3 20H.4 IS USED IN FUNCTION AS TEMP VAR
; R3,R4,R5 USED LOCALLY IN DELAY()
; ===================================
; Define Samples
; ====================================
MCLK EQU P1 .2 ; VALUE OF CLOCK LINE
MDATA EQU P1 .1 ; VALUE OF DATA LINE
SCAN EQU R1 ; VALUE OF THE SCAN CODE
RECV EQU R2 ; VALUE RECEIVED BY KEYBOARD
RECV2 EQU R6 ; THE VALUE RECEIVED SECONDLY
NEXTBIT EQU CY ; VALUE OF THE BIT WILL SENT NEXT
PARITY EQU 20H .1 ; VALUE OF PARITY
TEMP EQU 20H .2 ; THIS BIT IS FOR TEMPORITARY USE
TEMP1 EQU 20H .3 ; THIS BIT IS FOR TEMP USE
TEMP8BIT EQU 21H
LOOPCOUNTER EQU 30H ; COUNTER SPECIAL FOR SENDALLBIT
SCROLLLOCK EQU P1 .5
CAPSLOCK EQU P1 .6
NUMLOCK EQU P1 .7
ERROR_LIGHT EQU P1 .4 ; PARITY ERROR
ERROR_LIGHT_STOPBIT EQU P1 .3 ; STOP BIT RECEIVE ERROR
; ===================================
; ===================================
; ORG
; ===================================
ORG 00H
JMP MAIN
ORG 0003H
LJMP K1DOWN
ORG 000BH
LJMP K3DOWN
ORG 0013H
LJMP K2DOWN
; ============================================================
; MAIN
; ============================================================
MAIN:
; ==============================
; SET INTERRUPTER AND TIMER
mov ie , #10000101B ; 中断使能
mov ip , #00H ; 中断优先
mov tcon , #00000101b ; 中断为电平触发
; TIME0 AS A BUTTON
MOV TMOD , #06H
MOV TH0 , #0FFH
MOV TL0 , #0FFH
SETB ET0
SETB TR0
; ==============================
; ==============================
; SET CLK AND DATA LINE TO NORMAL STATUS
SETB MCLK
SETB MDATA
; ==============================
SETB CAPSLOCK ; CAPSLOCK OFF(1)
SETB NUMLOCK ; NUMLOCK OFF(1)
SETB SCROLLLOCK ; SCROLLLOCK OFF(1)
CHKSTATUS:
JNB MCLK , CHKSTATUS ; IF MCLK==0 THEN GOTO CHKSTATUS
JB MDATA , CHKSTATUS ; IF MDATA==1 THEN GOTO CHKSTAUS
; NOW MCLK=1 AND MDATA =0 ,READY TO RECEIVE DATA FROM PC
LCALL RECV_CHK_SEND ; RECEIVE DATA FROM PC
LJMP CHKSTATUS ; WAIT FOR BREAK
; ============================================================
; ///////MAIN
; ============================================================
; ===============================================================================================
; AREA FOR FUNCTION
; ===============================================================================================
LJMP ENDOFFILE
; ====================================
; IN THIS FUNCTION: RECEIVE ALL 10BIT DATA BY RECEIVEALLBIT() AND CHK WHETHER IT'S CORRECT THEN SEND CORRESPONDING SCANCODE TO PC
; ====================================
RECV_CHK_SEND:
CLR P1 .0 ; INDICATE START RECEIVEING
LCALL RECEIVEALLBIT ; RECV PARITY TEMP1
MOV A , RECV
CJNE A , #0EDH , RECV_CHK_SEND_END
; =====================
; RECV==EQ NOW SET LED
; CHKSTATUS_2:
; JNB MCLK,CHKSTATUS_2 ;IF MCLK==0 THEN GOTO CHKSTATUS
; JB MDATA,CHKSTATUS_2 ;IF MDATA==1 THEN GOTO CHKSTAUS
LCALL DELAY50
LCALL DELAY50
LCALL RECEIVEALLBIT ; RECV PARITY TEMP1
; ========================
; THE CODE IS RIGHT AFTER THIS ,TESTED BY MOV "RECV,#00000110"
MOV A , RECV
RRC A ; NOW C=LEAST BIT OF A
CPL C ; PC: C=1 ON ;C=0 OFF NOW IN KEYBOARD C=1 OFF(LIGHT OFF) C=0 ON(LIGHT ON)
MOV SCROLLLOCK , C
RRC A ; NOW C=LEAST BIT OF A
CPL C ; PC: C=1 ON ;C=0 OFF NOW IN KEYBOARD C=1 OFF(LIGHT OFF) C=0 ON(LIGHT ON)
MOV NUMLOCK , C
RRC A ; NOW C=LEAST BIT OF A
CPL C ; PC: C=1 ON ;C=0 OFF NOW IN KEYBOARD C=1 OFF(LIGHT OFF) C=0 ON(LIGHT ON)
MOV CAPSLOCK , C
SETB P1 .0
LJMP RECV_CHK_SEND_END
; /====================
RECV_CHK_SEND_END:
RET
; ====================================
; ////////IN THIS FUNCTION: RECEIVE ALL 10BIT DATA BY RECEIVEALLBIT() AND CHK WHETHER IT'S CORRECT THEN SEND CORRESPONDING SCANCODE TO PC
; ====================================
; ====================================
; RECIEVE ALL THE 10BIT DATA FROM PC AND CHECK WHETHER IT'S RIGHT
; SAVE THE 8BIT DATA TO RECV
; TEMP1: PARITY FIGURED OUT
; PARITY: PARITY RECEIVED
; ====================================
RECEIVEALLBIT:
MOV LOOPCOUNTER , #0008H
RECV8BIT_LOOP:
LCALL RECEIVEONE ; GET ONE BIT AND SAVE IT TO CY
RRC A ; RIGHT MOVE THIS BIT TO A
DJNZ LOOPCOUNTER , RECV8BIT_LOOP ; LOOP FOR 8 TIMES
MOV C , P ; C=P(THIS DOUBLE PARITY JUST RECEIVED
CPL C ; CHANG TO ODD PARITY
MOV TEMP1 , C ; STORE THE ODD PARITY TO TEMP1
MOV RECV , A ; RECV=A
LCALL RECEIVEONE ; GET PARITY BIT
MOV PARITY , C ; PARITY=C
LCALL RECEIVEONE ; PC PULL UP DATA LINE
MOV TEMP , C ; RECEIVE TERMINAL BIT(1)
; MOV P1,RECV ;JUST FOR TESTING
JNB MDATA , STOPBIT_ERROR ; 1==MDATA THEN RECEIVEALLBIT_ERROR
; SEND ACK
LCALL SENDACK
MOV C , TEMP1 ; C = PARITY FIGURED OUT
MOV A , #00H ; A=OOH
RRC A ; SAVE C TO A
MOV TEMP8BIT , A ; SAVE A TO TEMP8BIT
MOV C , PARITY
MOV A , #00H
RRC A
CJNE A , TEMP8BIT , PARITY_ERROR
; DATA RECEIV SUCCESSFUL
MOV SCAN , #00H
LCALL SENDALLBIT
; IF THE PROGRAM CAN RUN HERE,INDICATE ALL IS IN GOOD CONDICION
; SCAN 00H TO TELL PC ALL IN IN GOOD
; MOV SCAN,#00H
; LCALL SENDALLBIT
LJMP ENDOFSENDALLBIT
; ===================
; THE PARITY IS WRONG ,SO KEYBOARD RECEIVED A WRONG DATA
PARITY_ERROR:
CLR ERROR_LIGHT
; MOV SCAN,#0FFH
; LCALL SENDALLBIT
; /==================
LJMP ENDOFSENDALLBIT
; ===================
; STOPBIT ERROR
STOPBIT_ERROR:
CLR ERROR_LIGHT_STOPBIT
; MOV SCAN,#0FFH
; LCALL SENDALLBIT
LJMP ENDOFSENDALLBIT
ENDOFSENDALLBIT:
RET
; ====================================
; /////////RECIEVE ALL THE 10BIT DATA FROM PC AND CHECK WHETHER IT'S RIGHT
; /////////SAVE THE 8BIT DATA TO RECV
; ====================================
; ====================================
; SENDACK
; ====================================
SENDACK:
LCALL DELAY15
CLR MDATA
LCALL DELAY5
CLR MCLK
LCALL DELAY40
SETB MCLK
LCALL DELAY5
SETB MDATA
RET
; //==================================
; ====================================
; RECEIVE ONE BIT DATA FROM PC
; SAVE THIS BIT TO CY
; ====================================
RECEIVEONE:
LCALL DELAY20
CLR MCLK
LCALL DELAY40
SETB MCLK
LCALL DELAY20
MOV C , MDATA ; SAVE THIS BIT OF DATA TO CY,SAVE IT TO RECV LATER
RET
; ====================================
; /////RECEIVE ONE BIT DATA FROM PC
; ====================================
; ====================================
; INVOKE THIS FUNCTION WHEN K1 IS DOWN
; ====================================
K1DOWN:
MOV SCAN , #01CH
LCALL SENDALLBIT
MOV SCAN , #0F0H
LCALL SENDALLBIT
MOV SCAN , #01CH
LCALL SENDALLBIT
; LCALL DELAY ;DON'T PRINT SO FAST
RETI
; ====================================
; //////INVOKE THIS FUNCTION WHEN K1 IS DOWN
; ====================================
; ====================================
; INVOKE THIS FUNCTION WHEN K2 IS DOWN
; ====================================
K2DOWN:
MOV SCAN , #032H
LCALL SENDALLBIT
MOV SCAN , #0F0H
LCALL SENDALLBIT
MOV SCAN , #032H
LCALL SENDALLBIT
; LCALL DELAY ;DON'T PRINT SO FAST
RETI
; ====================================
; //////INVOKE THIS FUNCTION WHEN K2 IS DOWN
; ====================================
; ====================================
; INVOKE THIS FUNCTION WHEN K3 IS DOWN
; ====================================
K3DOWN:
MOV SCAN , #021H
LCALL SENDALLBIT
MOV SCAN , #0F0H
LCALL SENDALLBIT
MOV SCAN , #021H
LCALL SENDALLBIT
; LCALL DELAY ;DON'T PRINT SO FAST
RETI
; ====================================
; //////INVOKE THIS FUNCTION WHEN K3 IS DOWN
; ====================================
; ====================================
; SEND ALL 11 BIT DATA
; ====================================
SENDALLBIT:
; THE VAR SCANCODE MUST BE SET BEFORE THE FUNCTION
; SET CLK AND DATA LINE TO 1
INIT:
SETB MCLK ;
SETB MDATA ;
; CHECK WHETHER THE CLK AND DATA IS IN STATE THAT CAN TRANSFER DATA
CHKCLKHIGH:
JNB MCLK , CHKCLKHIGH ; IF CLK=0 THEN GOTO CHKCLKHIGH ELSE CONTINUE actually,this is the cache,wait for clk=1 to send the data
LCALL DELAY50 ; DELAY 50us
JNB MCLK , CHKCLKHIGH ;
JNB MDATA , CHKCLKHIGH ; IF DATA=0 THEN GOTO CHKCLKHIGH ELSE CONTINUE
; NOW CLK=1 FOR 50US AND DATA=1
LCALL DELAY20 ; ;DELAY 20US
; ================================
; CLK AND DATA CHECK FINISHED ,START DATA TRANSFAN
; ================================
STARTSEND:
CLR NEXTBIT ; SET START BIT ;1 PR
LCALL SENDBIT ; SENT THE START BIT ;170 PR
; SEND SCAN CODE
; NOW SCAN IS SET BEFOR SENDALLBIT()
; MOV SCAN,#035H ;LET SCAN= THE SCAN CODE OF KEY A ;2 PR
LCALL SENDSCAN ; SEND THE SCAN CODE ;1123 PR
; SEND PARITY ; #### COULD BE BETTER IN SENDING PARITY #########
LCALL CALPARITY
MOV C , PARITY
LCALL SENDBIT ; 140 PR
; SEND TERMINAL SIGN
SETB NEXTBIT ; TERMINAL SIGN=1 ;1 PR
LCALL SENDBIT ; 140 PR
LCALL DELAY50 ; DELAY 50us
LCALL DELAY20 ; DELAY 50us
; FINISHED SENDING DATA USED 1950 PERIODS
RET ; SENDALLBIT END
; =====================================
; =====================================
; long time delay
; =====================================
Delay:
MOV R3 , #000H
MOV R4 , #000H
MOV R5 , #0DH
Delay_Loop:
DJNZ R3 , Delay_Loop
DJNZ R4 , Delay_Loop
DJNZ R5 , Delay_Loop
RET
; =====================================
; =====================================================
; SEND THE SCAN CODE IN VAR SCAN
; PERIODS:1123 PR
; =====================================================
SENDSCAN:
CLR C ; 1 PR
MOV A , SCAN ; 2 PR
RRC A ; MOVE RIGHT ;1 PR
LCALL SENDBIT ; SEND 7TH ;140 PR
RRC A ; MOVE RIGHT ;1 PR
LCALL SENDBIT ; SEND 6TH ;140 PR
RRC A ; MOVE RIGHT ;1 PR
LCALL SENDBIT ; SEND 5TH ;170 PR
RRC A ; MOVE RIGHT ;1 PR
LCALL SENDBIT ; SEND 4TH ;140 PR
RRC A ; MOVE RIGHT ;1 PR
LCALL SENDBIT ; SEND 3TH ;140 PR
RRC A ; MOVE RIGHT ;1 PR
LCALL SENDBIT ; SEND 2TH ;140 PR
RRC A ; MOVE RIGHT ;1 PR
LCALL SENDBIT ; SEND 1TH ;140 PR
RRC A ; MOVE RIGHT ;1 PR
LCALL SENDBIT ; SEND 0TH ;140 PR
RET
; =====================================================
; =====================================================
; SEND THE NEXTBIT
; PERIODS:138 PERIODS
; =====================================================
SENDBIT:
MOV MDATA , C ; 1 period
LCALL DELAY20 ; 42 PERIODS
CLR MCLK ; PULL DOWN THE CLOCK LINE
LCALL DELAY40 ; 82 PERIODS
SETB MCLK ; 1 PERIODS
LCALL DELAY20 ; 12 PERIODS
RET
; =====================================================
; ======================================================
; SUB FOR DELAY 16US
; RAM USED:R0
; ======================================================
DELAY16:
MOV R0 , #003H ; 2
DELAY16_IN:DJNZ R0 , DELAY16_IN ; THIS COMMAND WILL BE EXCUTE FOR 15 TIMES, 2period
RET
; ======================================================
; ======================================================
; SUB FOR DELAY 32US
; RAM USED:R0
; ======================================================
DELAY32:
MOV R0 , #00EH ;
DELAY32_IN:DJNZ R0 , DELAY32_IN ; THIS COMMAND WILL BE EXCUTE FOR 31 TIMES, 2period
RET
; ======================================================
; ======================================================
; SUB FOR DELAY 50US correct?
; RAM USED:R0
; ======================================================
DELAY50US:
MOV R0 , #01aH ;
DELAY50_LOOP:DJNZ R0 , DELAY50_LOOP ; THIS COMMAND WILL BE EXCUTE FOR 31 TIMES, 2period
RET
; ======================================================
; ======================================================
; SUB FOR DELAY 20US
; RAM USED:R0
; periods:TOTAL 40PERIODS
; ======================================================
DELAY20:
MOV R0 , #013H ; RUN 19TIMES 2period
DELAY20_IN:DJNZ R0 , DELAY20_IN ; THIS COMMAND WILL BE EXCUTE FOR 19 TIMES, 2period
RET
; ======================================================
; ======================================================
; SUB FOR DELAY 5US
; RAM USED:R0
; periods:
; ======================================================
DELAY5:
MOV R0 , #004H ; RUN 10TIMES ;2period
DELAY5_IN:DJNZ R0 , DELAY5_IN ; THIS COMMAND WILL BE EXCUTE FOR 4 TIMES, 2period
RET
; ======================================================
; ======================================================
; SUB FOR DELAY 20US correct?
; RAM USED:R0
; periods:TOTAL 40PERIODS
; ======================================================
DELAY20US:
MOV R0 , #00DH ; RUN 19TIMES 2period
DELAY20US_LOOP:DJNZ R0 , DELAY20US_LOOP ; THIS COMMAND WILL BE EXCUTE FOR 19 TIMES, 2period
RET
; ======================================================
; ======================================================
; SUB FOR DELAY 50US
; RAM USED:R0
; PERIODS:100 PERIODS
; ======================================================
DELAY50:
MOV R0 , #0B1H
DELAY50_IN:DJNZ R0 , DELAY50_IN ;
RET
; ======================================================
; ======================================================
; SUB FOR DELAY 30US
; RAM USED:R0
; PERIODS:60 PERIODS
; ======================================================
DELAY30:
MOV R0 , #01DH
DELAY30_IN:DJNZ R0 , DELAY30_IN ;
RET
; ======================================================
; ======================================================
; SUB FOR DELAY 15US
; RAM USED:R0
; ======================================================
DELAY15:
MOV R0 , #00EH
DELAY15_IN:DJNZ R0 , DELAY15_IN ;
RET
; ======================================================
; ======================================================
; SUB FOR DELAY 40US
; RAM USED:R0
; PERIODS:80 PERIODS
; ======================================================
DELAY40:
MOV R0 , #27H
DELAY40_IN:DJNZ R0 , DELAY40_IN ;
RET
; ======================================================
; ======================================================
; CACULATE THE PARITY OF THE CODE
; RAM CHANGED:A,C,PARITY
; INPUT :SCAN
; RETURN VAR:PARITY
; ======================================================
CALPARITY:
MOV A , SCAN
MOV C , P
CPL C
MOV PARITY , C
RET
; ======================================================
; ===================================================================================================================
ENDOFFILE:
END ; END OF THE PROGRAM
; program
; check clk and data before every 8 bit data sending
; a function is created for send all 11bit data
; a function is created for parity calculating
; CAPSLOCK :BIG LETTER P1.3=0,SMALL LETTER P1.3=1
; =======================================
; =======================================
; VARS USED LOCALY
; R0 IS USED LOCALY AS A COUNTER
; 20H.1 20H.2 20H.3 20H.4 IS USED IN FUNCTION AS TEMP VAR
; R3,R4,R5 USED LOCALLY IN DELAY()
; ===================================
; Define Samples
; ====================================
MCLK EQU P1 .2 ; VALUE OF CLOCK LINE
MDATA EQU P1 .1 ; VALUE OF DATA LINE
SCAN EQU R1 ; VALUE OF THE SCAN CODE
RECV EQU R2 ; VALUE RECEIVED BY KEYBOARD
RECV2 EQU R6 ; THE VALUE RECEIVED SECONDLY
NEXTBIT EQU CY ; VALUE OF THE BIT WILL SENT NEXT
PARITY EQU 20H .1 ; VALUE OF PARITY
TEMP EQU 20H .2 ; THIS BIT IS FOR TEMPORITARY USE
TEMP1 EQU 20H .3 ; THIS BIT IS FOR TEMP USE
TEMP8BIT EQU 21H
LOOPCOUNTER EQU 30H ; COUNTER SPECIAL FOR SENDALLBIT
SCROLLLOCK EQU P1 .5
CAPSLOCK EQU P1 .6
NUMLOCK EQU P1 .7
ERROR_LIGHT EQU P1 .4 ; PARITY ERROR
ERROR_LIGHT_STOPBIT EQU P1 .3 ; STOP BIT RECEIVE ERROR
; ===================================
; ===================================
; ORG
; ===================================
ORG 00H
JMP MAIN
ORG 0003H
LJMP K1DOWN
ORG 000BH
LJMP K3DOWN
ORG 0013H
LJMP K2DOWN
; ============================================================
; MAIN
; ============================================================
MAIN:
; ==============================
; SET INTERRUPTER AND TIMER
mov ie , #10000101B ; 中断使能
mov ip , #00H ; 中断优先
mov tcon , #00000101b ; 中断为电平触发
; TIME0 AS A BUTTON
MOV TMOD , #06H
MOV TH0 , #0FFH
MOV TL0 , #0FFH
SETB ET0
SETB TR0
; ==============================
; ==============================
; SET CLK AND DATA LINE TO NORMAL STATUS
SETB MCLK
SETB MDATA
; ==============================
SETB CAPSLOCK ; CAPSLOCK OFF(1)
SETB NUMLOCK ; NUMLOCK OFF(1)
SETB SCROLLLOCK ; SCROLLLOCK OFF(1)
CHKSTATUS:
JNB MCLK , CHKSTATUS ; IF MCLK==0 THEN GOTO CHKSTATUS
JB MDATA , CHKSTATUS ; IF MDATA==1 THEN GOTO CHKSTAUS
; NOW MCLK=1 AND MDATA =0 ,READY TO RECEIVE DATA FROM PC
LCALL RECV_CHK_SEND ; RECEIVE DATA FROM PC
LJMP CHKSTATUS ; WAIT FOR BREAK
; ============================================================
; ///////MAIN
; ============================================================
; ===============================================================================================
; AREA FOR FUNCTION
; ===============================================================================================
LJMP ENDOFFILE
; ====================================
; IN THIS FUNCTION: RECEIVE ALL 10BIT DATA BY RECEIVEALLBIT() AND CHK WHETHER IT'S CORRECT THEN SEND CORRESPONDING SCANCODE TO PC
; ====================================
RECV_CHK_SEND:
CLR P1 .0 ; INDICATE START RECEIVEING
LCALL RECEIVEALLBIT ; RECV PARITY TEMP1
MOV A , RECV
CJNE A , #0EDH , RECV_CHK_SEND_END
; =====================
; RECV==EQ NOW SET LED
; CHKSTATUS_2:
; JNB MCLK,CHKSTATUS_2 ;IF MCLK==0 THEN GOTO CHKSTATUS
; JB MDATA,CHKSTATUS_2 ;IF MDATA==1 THEN GOTO CHKSTAUS
LCALL DELAY50
LCALL DELAY50
LCALL RECEIVEALLBIT ; RECV PARITY TEMP1
; ========================
; THE CODE IS RIGHT AFTER THIS ,TESTED BY MOV "RECV,#00000110"
MOV A , RECV
RRC A ; NOW C=LEAST BIT OF A
CPL C ; PC: C=1 ON ;C=0 OFF NOW IN KEYBOARD C=1 OFF(LIGHT OFF) C=0 ON(LIGHT ON)
MOV SCROLLLOCK , C
RRC A ; NOW C=LEAST BIT OF A
CPL C ; PC: C=1 ON ;C=0 OFF NOW IN KEYBOARD C=1 OFF(LIGHT OFF) C=0 ON(LIGHT ON)
MOV NUMLOCK , C
RRC A ; NOW C=LEAST BIT OF A
CPL C ; PC: C=1 ON ;C=0 OFF NOW IN KEYBOARD C=1 OFF(LIGHT OFF) C=0 ON(LIGHT ON)
MOV CAPSLOCK , C
SETB P1 .0
LJMP RECV_CHK_SEND_END
; /====================
RECV_CHK_SEND_END:
RET
; ====================================
; ////////IN THIS FUNCTION: RECEIVE ALL 10BIT DATA BY RECEIVEALLBIT() AND CHK WHETHER IT'S CORRECT THEN SEND CORRESPONDING SCANCODE TO PC
; ====================================
; ====================================
; RECIEVE ALL THE 10BIT DATA FROM PC AND CHECK WHETHER IT'S RIGHT
; SAVE THE 8BIT DATA TO RECV
; TEMP1: PARITY FIGURED OUT
; PARITY: PARITY RECEIVED
; ====================================
RECEIVEALLBIT:
MOV LOOPCOUNTER , #0008H
RECV8BIT_LOOP:
LCALL RECEIVEONE ; GET ONE BIT AND SAVE IT TO CY
RRC A ; RIGHT MOVE THIS BIT TO A
DJNZ LOOPCOUNTER , RECV8BIT_LOOP ; LOOP FOR 8 TIMES
MOV C , P ; C=P(THIS DOUBLE PARITY JUST RECEIVED
CPL C ; CHANG TO ODD PARITY
MOV TEMP1 , C ; STORE THE ODD PARITY TO TEMP1
MOV RECV , A ; RECV=A
LCALL RECEIVEONE ; GET PARITY BIT
MOV PARITY , C ; PARITY=C
LCALL RECEIVEONE ; PC PULL UP DATA LINE
MOV TEMP , C ; RECEIVE TERMINAL BIT(1)
; MOV P1,RECV ;JUST FOR TESTING
JNB MDATA , STOPBIT_ERROR ; 1==MDATA THEN RECEIVEALLBIT_ERROR
; SEND ACK
LCALL SENDACK
MOV C , TEMP1 ; C = PARITY FIGURED OUT
MOV A , #00H ; A=OOH
RRC A ; SAVE C TO A
MOV TEMP8BIT , A ; SAVE A TO TEMP8BIT
MOV C , PARITY
MOV A , #00H
RRC A
CJNE A , TEMP8BIT , PARITY_ERROR
; DATA RECEIV SUCCESSFUL
MOV SCAN , #00H
LCALL SENDALLBIT
; IF THE PROGRAM CAN RUN HERE,INDICATE ALL IS IN GOOD CONDICION
; SCAN 00H TO TELL PC ALL IN IN GOOD
; MOV SCAN,#00H
; LCALL SENDALLBIT
LJMP ENDOFSENDALLBIT
; ===================
; THE PARITY IS WRONG ,SO KEYBOARD RECEIVED A WRONG DATA
PARITY_ERROR:
CLR ERROR_LIGHT
; MOV SCAN,#0FFH
; LCALL SENDALLBIT
; /==================
LJMP ENDOFSENDALLBIT
; ===================
; STOPBIT ERROR
STOPBIT_ERROR:
CLR ERROR_LIGHT_STOPBIT
; MOV SCAN,#0FFH
; LCALL SENDALLBIT
LJMP ENDOFSENDALLBIT
ENDOFSENDALLBIT:
RET
; ====================================
; /////////RECIEVE ALL THE 10BIT DATA FROM PC AND CHECK WHETHER IT'S RIGHT
; /////////SAVE THE 8BIT DATA TO RECV
; ====================================
; ====================================
; SENDACK
; ====================================
SENDACK:
LCALL DELAY15
CLR MDATA
LCALL DELAY5
CLR MCLK
LCALL DELAY40
SETB MCLK
LCALL DELAY5
SETB MDATA
RET
; //==================================
; ====================================
; RECEIVE ONE BIT DATA FROM PC
; SAVE THIS BIT TO CY
; ====================================
RECEIVEONE:
LCALL DELAY20
CLR MCLK
LCALL DELAY40
SETB MCLK
LCALL DELAY20
MOV C , MDATA ; SAVE THIS BIT OF DATA TO CY,SAVE IT TO RECV LATER
RET
; ====================================
; /////RECEIVE ONE BIT DATA FROM PC
; ====================================
; ====================================
; INVOKE THIS FUNCTION WHEN K1 IS DOWN
; ====================================
K1DOWN:
MOV SCAN , #01CH
LCALL SENDALLBIT
MOV SCAN , #0F0H
LCALL SENDALLBIT
MOV SCAN , #01CH
LCALL SENDALLBIT
; LCALL DELAY ;DON'T PRINT SO FAST
RETI
; ====================================
; //////INVOKE THIS FUNCTION WHEN K1 IS DOWN
; ====================================
; ====================================
; INVOKE THIS FUNCTION WHEN K2 IS DOWN
; ====================================
K2DOWN:
MOV SCAN , #032H
LCALL SENDALLBIT
MOV SCAN , #0F0H
LCALL SENDALLBIT
MOV SCAN , #032H
LCALL SENDALLBIT
; LCALL DELAY ;DON'T PRINT SO FAST
RETI
; ====================================
; //////INVOKE THIS FUNCTION WHEN K2 IS DOWN
; ====================================
; ====================================
; INVOKE THIS FUNCTION WHEN K3 IS DOWN
; ====================================
K3DOWN:
MOV SCAN , #021H
LCALL SENDALLBIT
MOV SCAN , #0F0H
LCALL SENDALLBIT
MOV SCAN , #021H
LCALL SENDALLBIT
; LCALL DELAY ;DON'T PRINT SO FAST
RETI
; ====================================
; //////INVOKE THIS FUNCTION WHEN K3 IS DOWN
; ====================================
; ====================================
; SEND ALL 11 BIT DATA
; ====================================
SENDALLBIT:
; THE VAR SCANCODE MUST BE SET BEFORE THE FUNCTION
; SET CLK AND DATA LINE TO 1
INIT:
SETB MCLK ;
SETB MDATA ;
; CHECK WHETHER THE CLK AND DATA IS IN STATE THAT CAN TRANSFER DATA
CHKCLKHIGH:
JNB MCLK , CHKCLKHIGH ; IF CLK=0 THEN GOTO CHKCLKHIGH ELSE CONTINUE actually,this is the cache,wait for clk=1 to send the data
LCALL DELAY50 ; DELAY 50us
JNB MCLK , CHKCLKHIGH ;
JNB MDATA , CHKCLKHIGH ; IF DATA=0 THEN GOTO CHKCLKHIGH ELSE CONTINUE
; NOW CLK=1 FOR 50US AND DATA=1
LCALL DELAY20 ; ;DELAY 20US
; ================================
; CLK AND DATA CHECK FINISHED ,START DATA TRANSFAN
; ================================
STARTSEND:
CLR NEXTBIT ; SET START BIT ;1 PR
LCALL SENDBIT ; SENT THE START BIT ;170 PR
; SEND SCAN CODE
; NOW SCAN IS SET BEFOR SENDALLBIT()
; MOV SCAN,#035H ;LET SCAN= THE SCAN CODE OF KEY A ;2 PR
LCALL SENDSCAN ; SEND THE SCAN CODE ;1123 PR
; SEND PARITY ; #### COULD BE BETTER IN SENDING PARITY #########
LCALL CALPARITY
MOV C , PARITY
LCALL SENDBIT ; 140 PR
; SEND TERMINAL SIGN
SETB NEXTBIT ; TERMINAL SIGN=1 ;1 PR
LCALL SENDBIT ; 140 PR
LCALL DELAY50 ; DELAY 50us
LCALL DELAY20 ; DELAY 50us
; FINISHED SENDING DATA USED 1950 PERIODS
RET ; SENDALLBIT END
; =====================================
; =====================================
; long time delay
; =====================================
Delay:
MOV R3 , #000H
MOV R4 , #000H
MOV R5 , #0DH
Delay_Loop:
DJNZ R3 , Delay_Loop
DJNZ R4 , Delay_Loop
DJNZ R5 , Delay_Loop
RET
; =====================================
; =====================================================
; SEND THE SCAN CODE IN VAR SCAN
; PERIODS:1123 PR
; =====================================================
SENDSCAN:
CLR C ; 1 PR
MOV A , SCAN ; 2 PR
RRC A ; MOVE RIGHT ;1 PR
LCALL SENDBIT ; SEND 7TH ;140 PR
RRC A ; MOVE RIGHT ;1 PR
LCALL SENDBIT ; SEND 6TH ;140 PR
RRC A ; MOVE RIGHT ;1 PR
LCALL SENDBIT ; SEND 5TH ;170 PR
RRC A ; MOVE RIGHT ;1 PR
LCALL SENDBIT ; SEND 4TH ;140 PR
RRC A ; MOVE RIGHT ;1 PR
LCALL SENDBIT ; SEND 3TH ;140 PR
RRC A ; MOVE RIGHT ;1 PR
LCALL SENDBIT ; SEND 2TH ;140 PR
RRC A ; MOVE RIGHT ;1 PR
LCALL SENDBIT ; SEND 1TH ;140 PR
RRC A ; MOVE RIGHT ;1 PR
LCALL SENDBIT ; SEND 0TH ;140 PR
RET
; =====================================================
; =====================================================
; SEND THE NEXTBIT
; PERIODS:138 PERIODS
; =====================================================
SENDBIT:
MOV MDATA , C ; 1 period
LCALL DELAY20 ; 42 PERIODS
CLR MCLK ; PULL DOWN THE CLOCK LINE
LCALL DELAY40 ; 82 PERIODS
SETB MCLK ; 1 PERIODS
LCALL DELAY20 ; 12 PERIODS
RET
; =====================================================
; ======================================================
; SUB FOR DELAY 16US
; RAM USED:R0
; ======================================================
DELAY16:
MOV R0 , #003H ; 2
DELAY16_IN:DJNZ R0 , DELAY16_IN ; THIS COMMAND WILL BE EXCUTE FOR 15 TIMES, 2period
RET
; ======================================================
; ======================================================
; SUB FOR DELAY 32US
; RAM USED:R0
; ======================================================
DELAY32:
MOV R0 , #00EH ;
DELAY32_IN:DJNZ R0 , DELAY32_IN ; THIS COMMAND WILL BE EXCUTE FOR 31 TIMES, 2period
RET
; ======================================================
; ======================================================
; SUB FOR DELAY 50US correct?
; RAM USED:R0
; ======================================================
DELAY50US:
MOV R0 , #01aH ;
DELAY50_LOOP:DJNZ R0 , DELAY50_LOOP ; THIS COMMAND WILL BE EXCUTE FOR 31 TIMES, 2period
RET
; ======================================================
; ======================================================
; SUB FOR DELAY 20US
; RAM USED:R0
; periods:TOTAL 40PERIODS
; ======================================================
DELAY20:
MOV R0 , #013H ; RUN 19TIMES 2period
DELAY20_IN:DJNZ R0 , DELAY20_IN ; THIS COMMAND WILL BE EXCUTE FOR 19 TIMES, 2period
RET
; ======================================================
; ======================================================
; SUB FOR DELAY 5US
; RAM USED:R0
; periods:
; ======================================================
DELAY5:
MOV R0 , #004H ; RUN 10TIMES ;2period
DELAY5_IN:DJNZ R0 , DELAY5_IN ; THIS COMMAND WILL BE EXCUTE FOR 4 TIMES, 2period
RET
; ======================================================
; ======================================================
; SUB FOR DELAY 20US correct?
; RAM USED:R0
; periods:TOTAL 40PERIODS
; ======================================================
DELAY20US:
MOV R0 , #00DH ; RUN 19TIMES 2period
DELAY20US_LOOP:DJNZ R0 , DELAY20US_LOOP ; THIS COMMAND WILL BE EXCUTE FOR 19 TIMES, 2period
RET
; ======================================================
; ======================================================
; SUB FOR DELAY 50US
; RAM USED:R0
; PERIODS:100 PERIODS
; ======================================================
DELAY50:
MOV R0 , #0B1H
DELAY50_IN:DJNZ R0 , DELAY50_IN ;
RET
; ======================================================
; ======================================================
; SUB FOR DELAY 30US
; RAM USED:R0
; PERIODS:60 PERIODS
; ======================================================
DELAY30:
MOV R0 , #01DH
DELAY30_IN:DJNZ R0 , DELAY30_IN ;
RET
; ======================================================
; ======================================================
; SUB FOR DELAY 15US
; RAM USED:R0
; ======================================================
DELAY15:
MOV R0 , #00EH
DELAY15_IN:DJNZ R0 , DELAY15_IN ;
RET
; ======================================================
; ======================================================
; SUB FOR DELAY 40US
; RAM USED:R0
; PERIODS:80 PERIODS
; ======================================================
DELAY40:
MOV R0 , #27H
DELAY40_IN:DJNZ R0 , DELAY40_IN ;
RET
; ======================================================
; ======================================================
; CACULATE THE PARITY OF THE CODE
; RAM CHANGED:A,C,PARITY
; INPUT :SCAN
; RETURN VAR:PARITY
; ======================================================
CALPARITY:
MOV A , SCAN
MOV C , P
CPL C
MOV PARITY , C
RET
; ======================================================
; ===================================================================================================================
ENDOFFILE:
END ; END OF THE PROGRAM