MIPS - Segundos

MIPS - Seconds

org 0h ;power-on reset JMP Main org 0bh ;timer 0 interrupt JMP TC0int org 100h ;mainline code main: SETB P3.0 MOV R1, #00h MOV R3, #00h MOV DPTR, #TABLE LOOP: MOV A,R1 MOVC A, @A+DPTR MOV R3,A CJNE R3, #0 ,NEXT JMP final NEXT: MOV P1,A INC R1 CALL Init ;initialize RTC CALL TC0int CJNE R1, #8, LOOP jmp final org 0020h TABLE: DB 11111110b DB 11111101b DB 11111011b DB 11110111b DB 11101111b DB 11011111b DB 10111111b DB 01111111b DB 00000000b ;;;;;;; ;R0 acts as a decrementing variable counter ;TH0 and TL0 are the counter generating an interrupt when it ;reaches 0000h Init: MOV R0, #20h ;this gives R0 * 33ms delay = 1sec MOV R2, #00h MOV TH0, #80h MOV TL0, #00h ;timer 0 gives 33msecs between ; interrupts MOV TMOD, #01 ;C/T=0, mode 1 (16bit counter) MOV TCON, #10h ;start timer 0 running MOV IE, #82h ;enable all interrupt control bit ;enable interrupt for timer 0 RET ;Timer Counter Zero Interrupt Service Routine TC0int: DEC R0 ;decrement counter variable MOV B, R0 ;move into accumulator JNZ TC0Exit ;if not zero then return from interrupt MOV R0, #20h ;re-load initial values in R0 INC R2 ;seconds = seconds + 1 MOV B, R2 ;get seconds variable ;SUBB B, #60 ;if seconds >= 60 ;JNZ TC0Exit ret TC0Exit: MOV TH0, #80h MOV TL0, #00h CLR TF0 RET final: End