PIC16F877-20L Datasheet, PDF (35/218 Pages) Microchip Technology – 28/40-Pin 8-Bit CMOS FLASH Microcontrollers

3.4 PORTD and TRISD Registers
PORTD and TRISD are not implemented on the
PIC16F873 or PIC16F876.
PORTD is an 8-bit port with Schmitt Trigger input buff-
ers. Each pin is individually configureable 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.
PIC16F87X
FIGURE 3-7:
PORTD BLOCK DIAGRAM
(IN I/O PORT MODE)
Data
Bus
WR
Port
Data Latch
D
Q
CK
I/O pin⁽¹⁾
WR
TRIS
TRIS Latch
DQ
CK
RD
TRIS
Schmitt
Trigger
Input
Buffer
RD Port
Q
D
ENEN
Note 1: I/O pins have protection diodes to VDD and VSS.
TABLE 3-7: PORTD FUNCTIONS
Name
Bit#
Buffer Type
Function
RD0/PSP0
bit0
RD1/PSP1
bit1
RD2/PSP2
bit2
RD3/PSP3
bit3
RD4/PSP4
bit4
RD5/PSP5
bit5
RD6/PSP6
bit6
RD7/PSP7
bit7
ST/TTL⁽¹⁾
ST/TTL⁽¹⁾
ST/TTL⁽¹⁾
ST/TTL⁽¹⁾
ST/TTL⁽¹⁾
ST/TTL⁽¹⁾
ST/TTL⁽¹⁾
ST/TTL⁽¹⁾
Input/output port pin or parallel slave port bit0.
Input/output port pin or parallel slave port bit1.
Input/output port pin or parallel slave port bit2.
Input/output port pin or parallel slave port bit3.
Input/output port pin or parallel slave port bit4.
Input/output port pin or parallel slave port bit5.
Input/output port pin or parallel slave port bit6.
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.
TABLE 3-8: SUMMARY OF REGISTERS ASSOCIATED WITH PORTD
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.
 1998-2013 Microchip Technology Inc.
DS30292D-page 35