PIC16F871 Microchip Technology Inc., PIC16F871 Datasheet - Page 40

• Manufacturer Part Number: PIC16F871
• Description: 28/40-pin, 8-bit Cmos Flash Microcontrollers
• Manufacturer: Microchip Technology Inc.

PIC16F870/871
4.4
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.
TABLE 4-7:
TABLE 4-8:
DS30569B-page 38
08h
88h
89h
Legend: x = unknown, u = unchanged, - = unimplemented read as '0'. Shaded cells are not used by PORTD.
RD0/PSP0
RD1/PSP1
RD2/PSP2
RD3/PSP3
RD4/PSP4
RD5/PSP5
RD6/PSP6
RD7/PSP7
Legend:
Note 1:
Address
Name
PORTD and TRISD Registers
ST = Schmitt Trigger input, TTL = TTL input
Input buffers are Schmitt Triggers when in I/O mode and TTL buffers when in Parallel Slave Port mode.
PORTD
TRISD
TRISE
Name
Bit#
bit0
bit1
bit2
bit3
bit4
bit5
bit6
bit7
PORTD FUNCTIONS
SUMMARY OF REGISTERS ASSOCIATED WITH PORTD
PORTD Data Direction Register
Bit 7
RD7
IBF
Bit 6
RD6
OBF
Buffer Type
ST/TTL
ST/TTL
ST/TTL
ST/TTL
ST/TTL
ST/TTL
ST/TTL
ST/TTL
IBOV
Bit 5
RD5
(1)
(1)
(1)
(1)
(1)
(1)
(1)
(1)
PSPMODE
Bit 4
RD4
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.
Bit 3
RD3
—
PORTE Data Direction Bits
FIGURE 4-6:
Bit 2
RD2
Note 1: I/O pins have protection diodes to V
Data
Bus
WR
TRIS
WR
Port
RD Port
Bit 1
RD1
TRIS Latch
Function
Data Latch
D
D
CK
CK
RD TRIS
Q
Q
Bit 0
RD0
PORTD BLOCK DIAGRAM
(IN I/O PORT MODE)
 2003 Microchip Technology Inc.
Q
xxxx xxxx
1111 1111
0000 -111
POR, BOR
Value on:
EN
EN
Schmitt
Trigger
Input
Buffer
D
DD
and V
uuuu uuuu
1111 1111
0000 -111
I/O pin
Value on
RESETS
SS
all other
.
(1)