Datasheet

 1998-2013 Microchip Technology Inc. DS30289C-page 73
PIC17C7XX
FIGURE 10-3: RA3 BLOCK DIAGRAM FIGURE 10-4: RA4 AND RA5 BLOCK
DIAGRAM
TABLE 10-1: PORTA FUNCTIONS
TABLE 10-2: REGISTERS/BITS ASSOCIATED WITH PORTA
Note: I/O pin has protection diodes to VSS.
Data Bus
WR_PORTA
(Q4)
QD
Q
CK
RD_PORTA
(Q2)
QD
EN
Peripheral Data In
SDA Out
SSP Mode
'1'
Note: I/O pins have protection diodes to VDD and VSS.
Data Bus
RD_PORTA
(Q2)
Serial Port Output Signals
Serial Port Input Signal
OE
= SPEN,SYNC,TXEN, CREN, SREN for RA4
OE
= SPEN (SYNC+SYNC, CSRC) for RA5
Name Bit0 Buffer Type Function
RA0/INT bit0 ST Input or external interrupt input.
RA1/T0CKI bit1 ST Input or clock input to the TMR0 timer/counter and/or an external interrupt
input.
RA2/SS
/SCL bit2 ST Input/output or slave select input for the SPI, or clock input for the I
2
C bus.
Output is open drain type.
RA3/SDI/SDA bit3 ST Input/output or data input for the SPI, or data for the I
2
C bus.
Output is open drain type.
RA4/RX1/DT1 bit4 ST Input or USART1 Asynchronous Receive input, or
USART1 Synchronous Data input/output.
RA5/TX1/CK1 bit5 ST Input or USART1 Asynchronous Transmit output, or
USART1 Synchronous Clock input/output.
RBPU
bit7 — Control bit for PORTB weak pull-ups.
Legend: 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
MCLR, WDT
10h, Bank 0 PORTA
(1)
RBPU —
RA5/
TX1/CK1
RA4/
RX1/DT1
RA3/
SDI/SDA
RA2/
SS
/SCL
RA1/T0CKI RA0/INT
0-xx 11xx 0-uu 11uu
05h, Unbanked T0STA INTEDG T0SE
T0CS T0PS3 T0PS2 T0PS1 T0PS0 — 0000 000- 0000 000-
13h, Bank 0 RCSTA1 SPEN
RX9 SREN CREN — FERR OERR RX9D 0000 -00x 0000 -00u
15h, Bank 0 TXSTA1 CSRC
TX9 TXEN SYNC — — TRMT TX9D 0000 --1x 0000 --1u
Legend: x = unknown, u = unchanged, - = unimplemented, reads as '0'. Shaded cells are not used by PORTA.
Note 1: On any device RESET, these pins are configured as inputs.