Datasheet

Table Of Contents
Section 21 Clock Pulse Generator
REJ09B0140-0900 Rev. 9.00 Page 679 of 846
Sep 16, 2010
H8S/2215 Group
H8S/2215
Group
Ouptut port
External
interrupt
EXTAL
Request switchover of external clock
Interrupted external signal
External clock switchover signal
External clock 1
External clock 2
Control
cycle
Selector
Figure 21.13 Example of External Clock Switching Circuit
200 ns or more
(2)
(1)
(2)
(3)
(4)
(5)
Port setting (clock switchover)
Software standby mode transition
External clock switchover
External interrupt generation
(Input interrupt at least 200 ns after transition to software standby mode.)
Interrupt exception handling
(5)
SLEEP instruction
execution
Interrupt exception handling
Operation
External
clock 1
External
clock 2
(1)
Port setting
(3)
External clock
switchover
signal
EXTAL
Internal
clock φ
(4)
Wait time
External
interrupt
Active (external clock 2) Software standby mode Active (external clock 1)
Clock switchover
request
Figure 21.14 Example of External Clock Switchover Timing