Figure 21.13 Example Of External Clock Switchover Timing - Hitachi H8S/2215 Series Hardware Manual

External
clock 1
External
clock 2
Clock switchover
Operation
request
(1)
Port setting
External clock
switchover
signal
EXTAL
Internal
clock ø
External
interrupt

Figure 21.13 Example of External Clock Switchover Timing

Rev. 3.0, 10/02, page 606 of 686
SLEEP instruction
execution
(2)
Active (external clock 2)
(1) Port setting (clock switchover)
(2) Software standby mode transition
(3) External clock switchover
(4) External interrupt generation
(Input interrupt at least 200 ns after transition to software standby mode.)
(5) Interrupt exception handling
(3)
Wait time
200 ns or more (4)
Software standby mode
Interrupt exception handling
(5)
Active (external clock 1)