Intel mcs-48 manual Stop Tcnt Stop Timer/Event-Counter, 10110101011, Jump to Routine Intif ACe

INSTRUCTION SET

INIT: MOV R7,A	;MOVE ACC CONTENTS TO
	;LOCATION 7
SEL RB1	;SELECT REG BANK 1
MOV R7,#OFAH	;MOVE 'FA'HEX TO LOCATION 31

SEL RBO	;SELECT REG BANK 0
MOV A,R7	;RESTORE ACC FROM LOCATION 7
RETR	;RETURN - RESTORE PC AND PSW

STOP TCNT Stop Timer/Event-Counter

10110101011

This instruction is used to stop both time accumulation and event counting.

Example: Disable interrupt, but jump to interrupt routine after eight overflows and stop timer. Count overflows in register 7.

START: DIS TCNTI	;DISABLE TIMER INTERRUPT
CLR A	;CLEAR ACC TO ZEROS
MOV T,A	;MOVE ZEROS TO TIMER
MOV R7,A	;MOVE ZEROS TO REG 7
STRT T	;START TIMER
MAIN: JTF COUNT	;JUMP TO ROUTINE 'COUNT'
	;IF TF=1 AND CLEAR TIMER FLAG
JMP MAIN	;CLOSE LOOP
COUNT: INC R7	;INCREMENT REG 7
MOV A,R7	;MOVE REG 7 CONTENTS TO ACC
JB31NT	;JUMP TO ROUTINE 'INT'IF ACe
	;BIT 3 IS SET (REG 7=8)
JMP MAIN	;OTHERWISE RETURN TO ROUTINE
	;MAIN

INT: STOP TCNT ;STOP TIMER

JMP 7H ;JUMP TO LOCATION 7 (TIMER) ;INTERRUPT ROUTINE

Mnemonics copyright Intel Corporation 1976.

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