PIC16F87-E Datasheet, PDF (63/228 Pages) Microchip Technology – 18/20/28-Pin Enhan lashMicrocontrollers with nanoWatt Technology

FIGURE 5-10:
BLOCK DIAGRAM OF RB2/SDO/RX/DT PIN
SSPEN
SDO
1
0
PIC16F87/88
RBPU⁽²⁾
SPEN
DT
1
0
Data Bus
WR PORTB
Data Latch
DQ
CK
WR TRISB
DT Drive
TRIS Latch
D
Q
CK Q
RD TRISB
RD PORTB
SSPEN + SPEN
VDD
P
Weak
Pull-up
VDD
P
I/O pin⁽¹⁾
N
VSS
TTL
Input
Buffer
Q
D
EN
RX/DT
Schmitt Trigger
Buffer
RD PORTB
Note 1: I/O pins have diode protection to VDD and VSS.
2: To enable weak pull-ups, set the appropriate TRIS bit(s) and clear the RBPU bit.
 2005 Microchip Technology Inc.
DS30487C-page 61