Datasheet

 2010 Microchip Technology Inc. DS39933D-page 119
PIC18F87J90 FAMILY
TABLE 10-3: PORTA FUNCTIONS
TABLE 10-4: SUMMARY OF REGISTERS ASSOCIATED WITH PORTA
Pin Name Function
TRIS
Setting
I/O
I/O
Type
Description
RA0/AN0 RA0 0 O DIG LATA<0> data output; not affected by analog input.
1 I TTL PORTA<0> data input; disabled when analog input enabled.
AN0 1 I ANA A/D Input Channel 0. Default input configuration on POR; does not
affect digital output.
RA1/AN1/SEG18 RA1 0 O DIG LATA<1> data output; not affected by analog input.
1 I TTL PORTA<1> data input; disabled when analog input enabled.
AN1 1 I ANA A/D Input Channel 1. Default input configuration on POR; does not
affect digital output.
SEG18 x O ANA LCD Segment 18 output; disables all other pin functions.
RA2/AN2/V
REF-RA20 O DIG LATA<2> data output; not affected by analog input.
1 I TTL PORTA<2> data input; disabled when analog functions enabled.
AN2 1 I ANA A/D Input Channel 2. Default input configuration on POR.
V
REF- 1 I ANA A/D and comparator low reference voltage input.
RA3/AN3/V
REF+RA3 0 O DIG LATA<3> data output; not affected by analog input.
1 I TTL PORTA<3> data input; disabled when analog input enabled.
AN3 1 I ANA A/D Input Channel 3. Default input configuration on POR.
V
REF+ 1 I ANA A/D and comparator high reference voltage input.
RA4/T0CKI/
SEG14
RA4 0 O DIG LATA<4> data output.
1 I ST PORTA<4> data input. Default configuration on POR.
T0CKI x I ST Timer0 clock input.
SEG14 x O ANA LCD Segment 14 output; disables all other pin functions.
RA5/AN4/SEG15 RA5 0 O DIG LATA<5> data output; not affected by analog input.
1 I TTL PORTA<5> data input; disabled when analog input enabled.
AN4 1 I ANA A/D Input Channel 4. Default configuration on POR.
SEG15 x O ANA LCD Segment 15 output; disables all other pin functions.
OSC2/CLKO/RA6 OSC2 x O ANA Main oscillator feedback output connection (HS and HSPLL modes).
CLKO x O DIG System cycle clock output (F
OSC/4) (EC and ECPLL modes).
RA6 0 O DIG LATA<6> data output; disabled when FOSC2 Configuration bit is set.
1 I TTL PORTA<6> data input; disabled when FOSC2 Configuration bit is set.
OSC1/CLKI/RA7 OSC1 x I ANA Main oscillator input connection (HS and HSPLL modes).
CLKI x I ANA Main external clock source input (EC and ECPLL modes).
RA7 0 O DIG LATA<7> data output; disabled when FOSC2 Configuration bit is set.
1 I TTL PORTA<7> data input; disabled when FOSC2 Configuration bit is set.
Legend: O = Output, I = Input, ANA = Analog Signal, DIG = Digital Output, ST = Schmitt Trigger Buffer Input,
TTL = TTL Buffer Input, x = Don’t care (TRIS bit does not affect port direction or is overridden for this option).
Name Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0
Reset Values
on page
PORTA RA7
(1)
RA6
(1)
RA5 RA4 RA3 RA2 RA1 RA0 63
LATA LATA7
(1)
LATA6
(1)
LATA5 LATA4 LATA3 LATA2 LATA1 LATA0 62
TRISA TRISA7
(1)
TRISA6
(1)
TRISA5 TRISA4 TRISA3 TRISA2 TRISA1 TRISA0 62
ADCON1 TRIGSEL
— VCFG1 VCFG0PCFG3PCFG2PCFG1PCFG0 61
LCDSE1 SE15 SE14
SE13 SE12 SE11 SE10 SE09 SE08 61
LCDSE2
SE23 SE22 SE21 SE20 SE19 SE18 SE17 SE16 61
Legend: — = unimplemented, read as ‘0’. Shaded cells are not used by PORTA.
Note 1: These bits are enabled depending on the oscillator mode selected. When not enabled as PORTA pins, they are
disabled and read as ‘x’.