Datasheet

 2001-2013 Microchip Technology Inc. DS39598F-page 41
PIC16F818/819
FIGURE 5-5: BLOCK DIAGRAM OF RA5/MCLR/VPP PIN
FIGURE 5-6: BLOCK DIAGRAM OF RA6/OSC2/CLKO PIN
DQ
EN
MCLR Filter
RA5/MCLR/VPP
RD Port
MCLR Circuit
MCLRE
MCLRE
Data
Bus
RD TRIS
Schmitt Trigger
Buffer
VSS
VSS
Schmitt Trigger
Input Buffer
Data
Bus
QD
Q
CK
P
N
WR
PORTA
WR
TRISA
Data Latch
TRIS Latch
RD TRISA
RD PORTA
V
SS
VDD
RA6/OSC2/CLKO
Q
D
Q
CK
DQ
EN
Oscillator
Circuit
From OSC1
(F
OSC = 1x0,011)
P
N
VSS
VDD
CLKO (FOSC/4)
VDD
Note 1: I/O pins have protection diodes to VDD and VSS.
2: CLKO signal is 1/4 of the F
OSC frequency.
(FOSC = 1x1)
VSS
Schmitt Trigger
Input Buffer
(F
OSC = 1x0,011)