Datasheet

 2002 Microchip Technology Inc. Preliminary DS40044A-page 35
PIC16F627A/628A/648A
TABLE 5-1: PORTA FUNCTIONS
Name Function
Input
Type
Output
Type
Description
RA0/AN0 RA0 ST CMOS Bi-directional I/O port
AN0 AN — Analog comparator input
RA1/AN1 RA1 ST CMOS Bi-directional I/O port
AN1 AN — Analog comparator input
RA2/AN2/V
REF RA2 ST CMOS Bi-directional I/O port
AN2 AN — Analog comparator input
V
REF —ANVREF output
RA3/AN3/CMP1 RA3 ST CMOS Bi-directional I/O port
AN3 AN — Analog comparator input
CMP1 — CMOS Comparator 1 output
RA4/T0CKI/CMP2 RA4 ST OD Bi-directional I/O port. Output is open drain type.
T0CKI ST — External clock input for TMR0 or comparator output
CMP2 — OD Comparator 2 output
RA5/MCLR
/VPP RA5 ST —
Input port
MCLR
ST —
Master clear. When configured as MCLR
, this pin is an
active low RESET to the device. Voltage on MCLR
/VPP
must not exceed V
DD during normal device operation.
V
PP HV —
Programming voltage input.
RA6/OSC2/CLKOUT RA6 ST CMOS Bi-directional I/O port
OSC2 — XTAL Oscillator crystal output. Connects to crystal resonator in
Crystal Oscillator mode.
CLKOUT — CMOS In RC or INTOSC mode. OSC2 pin can output CLKOUT,
which has 1/4 the frequency of OSC1
RA7/OSC1/CLKIN RA7 ST CMOS Bi-directional I/O port
OSC1 XTAL — Oscillator crystal input. Connects to crystal resonator in
Crystal Oscillator mode.
CLKIN ST — External clock source input. RC biasing pin.
Legend: O = Output CMOS = CMOS Output P = Power
— = Not used I = Input ST = Schmitt Trigger Input
TTL = TTL Input OD = Open Drain Output AN = Analog