Intel 8XC251SA - Page 201

12-3
SPECIAL OPERATING MODES
Figure 12-2. Idle and Powerdown Clock Control
Table 12-1. Pin Conditions in Various Modes
Mode
Program
Memory
ALE
Pin
PSEN#
Pin
Port 0
Pins
Port 1
Pins
Port 2
Pins
Port 3
Pins
Reset Don’t Care Weak High Weak High Floating Weak High Weak High Weak High
Idle Internal 1 1 Data Data Data Data
Idle External 1 1 Floating Data Data Data
Powerdown Internal 0 0 Data Data Data Data
Powerdown External 0 0 Floating Data Data Data
ONCE Don’t Care Floating Floating Floating Weak High Weak High Weak High
A4160-01
XTAL2
XTAL1
C1
C2
OSC
PD#
Clock
Gen
IDL#
Interrupt,
Serial Port,
Timer Block
CPU