
PIC18C601/801
DS39541A-page 122
Advance Information
2001 Microchip Technology Inc.
FIGURE 9-18:
RH3:RH0 PINS BLOCK DIAGRAM IN SYSTEM BUS MODE
To Instruction Register
External Enable.
Address Out
Drive System
System Bus
Control
Data Bus
WR LATH
WR TRISH
RD PORTH
Data Latch
TRIS Latch
RD TRISH
TTL
Input
Buffer
I/O pin(1)
Q
D
CK
Q
D
CK
EN
QD
EN
RD LATD
or
PORTH
0
1
Port
Data
Instruction Read
Note 1: I/O pins have diode protection to VDD and VSS.