PIC16F684

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Contents

Overview

For a complete list of features, see this printout from the datasheet.

IMPORTANT: See PIC16F684 Registers for detailed information on registers.

Pinout

Pic16f684 pinout.png
Description of Pinout Labels
Label Description
V_{DD}\, + 5 V
V_{SS}\, Ground
V_{REF}\, External Voltage Reference
RA\#/RC\#\, PORTA/PORTC Programmable I/O
AN\#\, A/D Channel
INT\, External Interrupt Input
P1A/B/C/D\, PWM Output

Initialization

Configuring I/O

This section shows two sections of code that are used for setting up the I/O of the PIC. The INIT_IO function sets up the ports by setting their default value and their direction. The second function, INIT_ADC sets up the A/D converter.

INIT_IO	
	BCF 		STATUS,RP0 		;Bank 0
	CLRF 		PORTA 			;Init PORTA - initially set to LOW
	MOVLW 	B'000101'			;Set RA<0> as input
	MOVWF 		TRISA 			;	and set RA<5:1>
						;	as outputs

	BSF 		STATUS,RP0 		;Bank 1
	CLRF 		PORTC 			;Init PORTC - initially set to LOW
	MOVLW 	B'000000'			;Set RC<5:0> as outputs
	MOVWF 		TRISC

	CLRF		ANSEL			;Set all pins initially to digital I/O
	MOVLW	B'000001'
	MOVWF		ANSEL			;Set AN<0> (RA<0>) to Analog input
						;	RA<5:1> remain digital I/O
	RETURN

INIT_ADC
	BCF 		STATUS,RP0 		;Bank 0
        MOVLW   B'00000001'			; Set output to left justified
	MOVWF   	ADCON0			; Select AN<0> (RA<0>) as input
						; Internal Vref
						; Start ADC ON

	BSF 		STATUS,RP0 		;Bank 1
	CLRF		ADCON1
        MOVLW   B'00100000' 		        ;Set Clock TAD to 1.6us (Fosc/32)
        MOVWF   	ADCON1

	RETURN

Notice that the two following bits of code are equivalent:

        CLRF            PORTA

and

	MOVLW 	B'000000'
	MOVWF 		PORTA

Setting Up for PWM Output

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