
PIC16F870/871
DS30569B-page 34
2003 Microchip Technology Inc.
TABLE 4-1:
PORTA FUNCTIONS
TABLE 4-2:
SUMMARY OF REGISTERS ASSOCIATED WITH PORTA
Name
Bit#
Buffer
Function
RA0/AN0
bit0
TTL
Input/output or analog input.
RA1/AN1
bit1
TTL
Input/output or analog input.
RA2/AN2
bit2
TTL
Input/output or analog input.
RA3/AN3/VREF
bit3
TTL
Input/output or analog input or VREF.
RA4/T0CKI
bit4
ST
Input/output or external clock input for Timer0. Output is open drain type.
RA5/AN4
bit5
TTL
Input/output or analog input.
Legend: TTL = TTL input, ST = Schmitt Trigger input
Address
Name
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
Value on:
POR, BOR
Value on
all other
RESETS
05h
PORTA
—
RA5
RA4
RA3
RA2
RA1
RA0
--0x 0000 --0u 0000
85h
TRISA
—
PORTA Data Direction Register
--11 1111 --11 1111
9Fh
ADCON1 ADFM
—
PCFG3
PCFG2 PCFG1 PCFG0 --0- 0000 --0- 0000
Legend:
x
= unknown, u = unchanged, - = unimplemented locations read as '0'.
Shaded cells are not used by PORTA.