beep.asm

来自「VCP201_CODE is a FPGA source code.」· 汇编 代码 · 共 29 行

;****************************************************************************
;FUNCTION: THIS ROUTINE IS TO GENERATE BEEP SOUND.  THE INPUT IS NUMBER OF 
;          OF BEEPS TO BE GENERATED AND IS CONTAINED IN W REGISTER.  THE
;          OUTPUT IS A 4KHZ BEEP SOUND WITH ON AND OFF DURATION OF ABOUT 0.2
;          SECONDS. THE 4KHZ SIGNAL IS GENERATED BY LOOPING THE HIGH AND LOW
;          PULSE IS DONE BY TAKING OUT ONE OF THE 8 BITS OF THE BEEP_CNT WHICH
;          IS A SOFTWARE FREE-RUNNING COUNTER.
;          THE BEEP DURATION IS CONTROLLED BY THE BUFFER TMR_BEEP.
;          
;SUBROUTINE CALL: NIL
;****************************************************************************
p_beep:
;	bsf	STATUS,RP0
;	movwf	beep_cnt	;W->beep_cnt for No. of Beep count
;	bcf	STATUS,RP0 	

	bcf	STATUS,RP0
	addlw	0x10
        movwf	buzctrl

	clrf	buzo

;beep_busy:
;	btfsc	buzctrl,7
;	goto	beep_busy

	return