PIC16F870/871
TABLE 3-1:
Name
PORTA FUNCTIONS
Bit#
Buffer
Function
RA0/AN0
bit0
bit1
bit2
bit3
bit4
TTL
TTL
TTL
TTL
ST
Input/output or analog input
Input/output or analog input
Input/output or analog input
RA1/AN1
RA2/AN2
RA3/AN3/VREF
RA4/T0CKI
Input/output or analog input or VREF
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
TABLE 3-2:
SUMMARY OF REGISTERS ASSOCIATED WITH PORTA
Value on
all
other
resets
Value on:
POR,
BOR
Address Name
Bit 7 Bit 6 Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
--0x 0000 --0u 0000
--11 1111 --11 1111
--0- 0000 --0- 0000
05h
85h
9Fh
PORTA
—
—
—
—
—
RA5
RA4
RA3
RA2
RA1
RA0
TRISA
PORTA Data Direction Register
PCFG3 PCFG2 PCFG1 PCFG0
ADCON1 ADFM
—
—
Legend: x= unknown, u= unchanged, -= unimplemented locations read as '0'. Shaded cells are not used by
PORTA.
DS30569A-page 28
Preliminary
1999 Microchip Technology Inc.
MICROCHIP [ MICROCHIP ]
