读取CMOS时钟并显示

读取年月日及当前时间

ESCAPE      EQU 1BH
CMOS_PORT   EQU 70H
CMOS_REGA   EQU 0AH
UPDATE_FLAG EQU 80H
CMOS_SEC    EQU 00H
CMOS_MIN    EQU 02H
CMOS_HOUR   EQU 04H
CMOS_DAY    EQU 07H
CMOS_MONTH  EQU 08H
CMOS_YEAR   EQU 09H
DATA SEGMENT
    DATETIME DB 'YY-MM-DD HH:MI:SS'
    DT_LEN = $ - OFFSET DATETIME
DATA ENDS
STACK SEGMENT
    DB 16 DUP(?)
STACK ENDS
CODE SEGMENT
    ASSUME CS:CODE,DS:DATA,SS:STACK
START:
    MOV AX,DATA
    MOV DS,AX
    MOV AX,STACK
    MOV SS,AX
    ADD SP,-16
@@:
    MOV SI,OFFSET DATETIME
    MOV AL,CMOS_REGA
    OUT CMOS_PORT,AL
    JMP $+2
    IN  AL,CMOS_PORT+1
    TEST AL,UPDATE_FLAG
    JNZ @B
    ;GET YEAR
    MOV AL,CMOS_YEAR
    OUT CMOS_PORT,AL
    JMP $+2
    IN  AL,CMOS_PORT+1
    MOV AH,AL
    MOV CL,4
    SHR AH,CL
    AND AL,00001111B
    ADD AH,30H
    ADD AL,30H
    MOV [SI],AH
    MOV [SI+1],AL
    ADD SI,3    
    ;GET MONTH
    MOV AL,CMOS_MONTH
    OUT CMOS_PORT,AL
    JMP $+2
    IN  AL,CMOS_PORT+1
    MOV AH,AL
    MOV CL,4
    SHR AH,CL
    AND AL,00001111B
    ADD AH,30H
    ADD AL,30H
    MOV [SI],AH
    MOV [SI+1],AL
    ADD SI,3
    ;GET DAY
    MOV AL,CMOS_DAY
    OUT CMOS_PORT,AL
    JMP $+2
    IN  AL,CMOS_PORT+1
    MOV AH,AL
    MOV CL,4
    SHR AH,CL
    AND AL,00001111B
    ADD AH,30H
    ADD AL,30H
    MOV [SI],AH
    MOV [SI+1],AL
    ADD SI,3
    ;GET HOUR
    MOV AL,CMOS_HOUR
    OUT CMOS_PORT,AL
    JMP $+2
    IN  AL,CMOS_PORT+1
    MOV AH,AL
    MOV CL,4
    SHR AH,CL
    AND AL,00001111B
    ADD AH,30H
    ADD AL,30H
    MOV [SI],AH
    MOV [SI+1],AL
    ADD SI,3    
    ;GET MINUTE
    MOV AL,CMOS_MIN
    OUT CMOS_PORT,AL
    JMP $+2
    IN  AL,CMOS_PORT+1
    MOV AH,AL
    MOV CL,4
    SHR AH,CL
    AND AL,00001111B
    ADD AH,30H
    ADD AL,30H
    MOV [SI],AH
    MOV [SI+1],AL
    ADD SI,3
    ;GET SECOND
    MOV AL,CMOS_SEC
    OUT CMOS_PORT,AL
    JMP $+2
    IN  AL,CMOS_PORT+1
    MOV AH,AL
    MOV CL,4
    SHR AH,CL
    AND AL,00001111B
    ADD AH,30H
    ADD AL,30H
    MOV [SI],AH
    MOV [SI+1],AL
    ADD SI,3
    ;
    MOV SI,OFFSET DATETIME
    CALL DISPLAY
    ;
    MOV AH,1
    INT 16H    
    CMP AL,ESCAPE
    JZ _EXIT
    CALL CLEANKBBUF
    JMP @B
_EXIT:    
    MOV AH,4CH
    INT 21H
CLEANKBBUF PROC    
_AGAIN:
    MOV AH,1
    INT 16H
    JZ _OVER
    MOV AH,0
    INT 16H
    JMP _AGAIN
_OVER:
    RET    
CLEANKBBUF ENDP
DISPLAY PROC
    MOV AX,0B800H
    MOV ES,AX
    MOV AH,0F4H;087H   ;此处设置显示的属性即颜色IRGB
    MOV DI,(80*12+28)*2;(80列*25行)12表示显示的行(中间)/28表示显示起始列
    MOV CX,DT_LEN
S:  
    MOV AL,[SI]
    MOV ES:[DI],AX     ;AX中AH保存颜色，AL保存输出值/此处可以用AX或AL
    INC SI
    ADD DI,2
    LOOP S
    RET
DISPLAY ENDP     
CODE ENDS
END START

CMOS内容对照
地址   内容   地址   内容   地址   内容   地址   内容  
00h   Time   -   Seconds   20h   Reserved   40h   Extended   CMOS   60h   User   Password    
01h   Alarm   -   Seconds   21h   Reserved   41h   Extended   CMOS   61h   User   Password    
02h   Time   -   Minutes   22h   Reserved   42h   Extended   CMOS   62h   Extended   CMOS  
03h   Alarm   -   Minutes   23h   Reserved   43h   Extended   CMOS   63h   Extended   CMOS  
04h   Time   -   Hours   24h   Reserved   44h   Extended   CMOS   64h   Extended   CMOS  
05h   Alarm   -   Hours   25h   Reserved   45h   Extended   CMOS   65h   Extended   CMOS    
06h   Date   -   Day   of   the   week   26h   Reserved   46h   Extended   CMOS   66h   Extended   CMOS  
07h   Date   -   Day   27h   Reserved   47h   Extended   CMOS   67h   Extended   CMOS  
08h   Date   -   Month   28h   Reserved   48h   Extended   CMOS   68h   Extended   CMOS  
09h   Date   -   Year   29h   Reserved   49h   Extended   CMOS   69h   Extended   CMOS  
0Ah   Status   Register   A   2Ah   Reserved   4Ah   Extended   CMOS   6Ah   Extended   CMOS