Datasheet

PIC16F870/871
DS30569C-page 38  2000-2013 Microchip Technology Inc.
4.4 PORTD and TRISD Registers
This section is not applicable to the PIC16F870.
PORTD is an 8-bit port with Schmitt Trigger input buff-
ers. Each pin is individually configurable as an input or
output.
PORTD can be configured as an 8-bit wide micropro-
cessor port (parallel slave port) by setting control bit
PSPMODE (TRISE<4>). In this mode, the input buffers
are TTL.
FIGURE 4-6: PORTD BLOCK DIAGRAM
(IN I/O PORT MODE)
TABLE 4-7: PORTD FUNCTIONS
TABLE 4-8: SUMMARY OF REGISTERS ASSOCIATED WITH PORTD
Data
Bus
WR
Port
WR
TRIS
RD Port
Data Latch
TRIS Latch
RD TRIS
Schmitt
Trigger
Input
Buffer
I/O pin
(1)
Note 1: I/O pins have protection diodes to VDD and VSS.
QD
CK
QD
CK
EN
QD
EN
Name Bit# Buffer Type Function
RD0/PSP0 bit0
ST/TTL
(1)
Input/output port pin or parallel slave port bit0.
RD1/PSP1 bit1
ST/TTL
(1)
Input/output port pin or parallel slave port bit1.
RD2/PSP2 bit2
ST/TTL
(1)
Input/output port pin or parallel slave port bit2.
RD3/PSP3 bit3
ST/TTL
(1)
Input/output port pin or parallel slave port bit3.
RD4/PSP4 bit4
ST/TTL
(1)
Input/output port pin or parallel slave port bit4.
RD5/PSP5 bit5
ST/TTL
(1)
Input/output port pin or parallel slave port bit5.
RD6/PSP6 bit6
ST/TTL
(1)
Input/output port pin or parallel slave port bit6.
RD7/PSP7 bit7
ST/TTL
(1)
Input/output port pin or parallel slave port bit7.
Legend: ST = Schmitt Trigger input, TTL = TTL input
Note 1: Input buffers are Schmitt Triggers when in I/O mode and TTL buffers when in Parallel Slave Port mode.
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
08h PORTD RD7 RD6 RD5 RD4 RD3 RD2 RD1 RD0 xxxx xxxx uuuu uuuu
88h TRISD PORTD Data Direction Register 1111 1111 1111 1111
89h TRISE
IBF OBF IBOV PSPMODE — PORTE Data Direction Bits 0000 -111 0000 -111
Legend: x = unknown, u = unchanged, - = unimplemented read as '0'. Shaded cells are not used by PORTD.