Need Help! PIC16F877A Port Initialization - Electronic Circuits Projects Diagrams Free

Klitzie · 5th February 2008, 02:07 PM

I just want to ask how to correctly initialize a PORT in PIC16F877a cause its my first time using usually i used PIC16F84A due to more inputs a shift to pic16f877a but my problem is that i cannot correctly initialize PORTA of PIC16F877a due to the ADC function sharing with the port. Because i want to used my PORTA as an input for my sensors which i cannot distinguish either analog or digital.

Is the common sensor which is compose of IR and Phototransistor output an analog or digital signal?

**Nigel Goodwin** · 5th February 2008, 02:21 PM

Quote:

Originally Posted by Klitzie

I just want to ask how to correctly initialize a PORT in PIC16F877a cause its my first time using usually i used PIC16F84A due to more inputs a shift to pic16f877a but my problem is that i cannot correctly initialize PORTA of PIC16F877a due to the ADC function sharing with the port. Because i want to used my PORTA as an input for my sensors which i cannot distinguish either analog or digital.

The datasheet expalins it, or you could check my tutorials.

Quote:

Is the common sensor which is compose of IR and Phototransistor output an analog or digital signal?

Usually digital.

Pommie · 5th February 2008, 02:23 PM

If you look in the data sheet it has this code snippet to setup port A.

Code:

	BCF	STATUS,RP0
	BCF	STATUS,RP1	; Bank0
	CLRF	PORTA		; Initialize PORTA by
				; clearing output
				; data latches
	BSF	STATUS, RP0	; Select Bank 1
	MOVLW	0x06		; Configure all pins
	MOVWF	ADCON1		; as digital inputs
	MOVLW	0xCF		; Value used to
				; initialize data
				; direction
	MOVWF	TRISA		; Set RA<3:0> as inputs
				; RA<5:4> as outputs
				; TRISA<7:6>are always
				; read as '0'.

HTH

Mike.

Klitzie · 5th February 2008, 04:42 PM

Im using a pic-lite compiler it doing my program, im not good in assembly, can you convert this to a c code.

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5th February 2008, 02:07 PM	(permalink)
Klitzie	Need Help! PIC16F877A Port Initialization I just want to ask how to correctly initialize a PORT in PIC16F877a cause its my first time using usually i used PIC16F84A due to more inputs a shift to pic16f877a but my problem is that i cannot correctly initialize PORTA of PIC16F877a due to the ADC function sharing with the port. Because i want to used my PORTA as an input for my sensors which i cannot distinguish either analog or digital. Is the common sensor which is compose of IR and Phototransistor output an analog or digital signal?

5th February 2008, 04:42 PM	(permalink)
Klitzie	Im using a pic-lite compiler it doing my program, im not good in assembly, can you convert this to a c code.