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capture module problem

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amitaiwe

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capture module not working

Hi to all and thanks to all how helped my till now in my project,

I'm using a PIC16F877 and for some reason it's capture module doesn't work.
A loop in my code which job is to wait for the flag announcement of capturing
isn't set and there's a infinite loop of waiting for that to happen.

A DMM which is connected to the CCP2 leg shows a frequency but I'm not sure that
its a true value there, (although I have already seen that it measures exact frequency
and duty cycle) since it shows sometimes also a frequency when disconnected.

have I done the configuration and capture loop correctly?
The other sections of the code work properly.
Thank,
Amitai

Code:
LIST	P=PIC16F877
    	
include	<P16f877.inc>
org		0x00

	__CONFIG _LVP_OFF &_WDT_OFF &_PWRTE_OFF &_CP_OFF & _HS_OSC	

	reset:
	nop
	goto	start
	org		0x20

start:




; configuration
;-----------------------------------

; used_ registers:
	MUX_sel			EQU H'0021'  		; for not transmitting '000000000'
	del1			EQU H'0030'  		; for delay
	del2			EQU H'0031'  		; for delay
	to_transmit		EQU H'0050'  		; Frequency data register
	led1			EQU H'0070'  		; for led delay
	demo_tr			EQU H'0072'  		; demo transmit
	loop_mux		EQU H'0074'  		; demo transmit

	banksel		ADCON1
	movlw		0x07				; ADC PINS configured as a digital I/O									
	movwf		ADCON1

;UART/*/*/
	banksel		TRISC
	bsf	 	 	TRISC, 6 
	bsf		 	TRISC, 7	
	
	banksel  	TXSTA
	movlw    	0xA7        		; master, transmit EN, Async mode, Transmit Shift Register empty, BRGH =1
	movwf    	TXSTA	       		; Baud Rate = Fosc/(16(SPBRG+1)) , BRGH (baud rate) ignored in sync
	
	banksel		SPBRG
	movlw	 	0x03		   		; = d"16" which corresponds to 125Kbps with 8MHz clock
	movwf	 	SPBRG
	
	banksel  	RCSTA
	movlw    	0x80		  		; enable UART	
	movwf    	RCSTA
	
;PWM, timer2/*/*/
	banksel		TRISC
	bcf			TRISC, 2 			; make the CCP1 pin an output.
	
	banksel		T2CON
	movlw		0x04
	movwf		T2CON				; no post/Prescaler (1:1) , TMR2 ON
	
	banksel		PR2					; output frequency = 15000hz 	=			
	movlw		0x84
	movwf		PR2					; 1 / [(PR2) + 1] • 4 • TOSC •(TMR2 prescale value)
	
	banksel		CCPR1L				;duty cycle =(CCPR1L:CCP1CON<5:4>) • TOSC • (TMR2 prescale value)
	movlw		0x42				;           = 267 *1/8MHz = 50% d.c.
	movwf		CCPR1L				
	banksel		CCP1CON
	movlw		0x3C
	movwf		CCP1CON

;capture, timer1 /*/*/
	banksel		TRISC
	bsf			TRISC, 1 			; make the CCP2 pin an input.

	banksel		T1CON
	movlw		0x09				; Timer1 Input Clock Prescale 1:1, en TMR1
	movwf		T1CON				; , int clk (fosc/4) , oscillator en
	banksel		CCP2CON
	movlw		0x07
	movwf		CCP2CON				; Capture mode, every 16th rising edge 
	banksel		PIE2
	bcf			PIE2, CCP2IE		; avoid false interrupts 
	
;MUX select
	banksel		TRISD
	bcf			TRISD, 0
	bcf			TRISD, 1
	bcf			TRISD, 2

;LED general delay
	bcf			TRISD, 4
	bcf			TRISD, 5
	banksel		PORTD	
	bcf			PORTD, 4
	bcf			PORTD, 5
	
; end configuration --------------------------------------




;************ MAIN PROGRAM ***************
;*****************************************

main:
	
;MUX init
	movlw		0x07
	movwf		MUX_sel
	movlw		0x08
	movwf		loop_mux
	
;transmit check /*/*/*/*
    movlw		0x05					; demo check
	movwf		demo_tr
	tra:
	CALL		DELAY
	movf		demo_tr, w
	movwf		to_transmit 
	CALL 		transmitting_data
	decfsz		demo_tr
	goto		tra   	
	
main_loop:

Led_flicker:
	movlw 		0x30
	movwf		led1
	t2:
	CALL		DELAY
	decfsz		led1
	goto		t2
		
	bcf			PORTD,5
	bsf			PORTD,4		
		
	banksel		led1		
	movlw 		0x30
	movwf		led1
	t1:
	CALL		DELAY
	decfsz		led1
	goto		t1

	bcf			PORTD,4
	bsf			PORTD,5
;---end Led flicker

;capture frequency/*/*
	banksel		TMR1H	
	clrf		TMR1H
	clrf		TMR1L
	
	banksel		PIR2
	bcf			PIR2, CCP2IF
	check_capture:		
	btfss		PIR2, CCP2IF					; 1  = A TMR1 register capture occurred (must be cleared in software)
	goto		check_capture
	bcf			PIR2, CCP2IF
	
;transmitting data	
	banksel		CCPR2H							; transmit MSB
	movf		CCPR2H, w
	banksel		to_transmit
	movwf		to_transmit
	sublw		0xFF				; if data = FF change to FE
	btfsc		STATUS, Z
	CALL		data_change	
	CALL 		transmitting_data
	
	banksel		CCPR2L							; transmit LSB
	movf		CCPR2L, w
	banksel		to_transmit
	movwf		to_transmit
	sublw		0xFF				; if data = FF change to FE
	btfsc		STATUS, Z
	CALL		data_change
	CALL 		transmitting_data
		
;MUX select/*/*/
	
	movf		MUX_sel,w
	banksel		PORTD
	movwf		PORTD
	decf		MUX_sel, f
	decfsz		loop_mux
	goto		main_loop
	movlw		0x07
	movwf		MUX_sel
	movlw		0x08
	movwf		loop_mux
	
	movlw		0xFF							; send FF at end of buffers
	movwf		to_transmit
	CALL		transmitting_data
goto main_loop

	
				
;******** END MAIN LOOP ********************		

transmitting_data:	
	banksel		TXREG
	movwf   	TXREG					    	; writing to TXREG clears TXIF
    trans_wait2:
	btfss		PIR1, TXIF						; wait for the frame to be transmitted
	goto		trans_wait2
	CALL		DELAY
	return
	
data_change:
	movlw		0xFE
	movwf		to_transmit
	return
	
DELAY:
	movlw		0xFF
	movwf		del1
	movlw		0xFF
	movwf		del2
	
	loopa:
	decfsz		del1, f
	goto		loopa
	loopb:
	decfsz		del2, f
	goto		loopb
	return
		
end
 
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