HD64336901G Renesas Technology, HD64336901G Datasheet - Page 99

• Manufacturer Part Number: HD64336901G
• Description: (HD64xxx Series) 16-BIT MICROCONTROLLER
• Manufacturer: Renesas Technology

5.3
Figure 5.2 shows the state transition of the system clock.
Bit
1
0
Note: * Conditions for the state transition are as follows:
RC oscillator: Halted
External oscillator: Operated
System Clock Select Operation
Bit Name
OSCHLT
CKSTA
Reset state
When the external oscillation halt is detected while the backup function is enabled
When the external clock is switched to the internal RC clock by user software while
the backup function is disabled
Initial
Value
1
0
Figure 5.2 State Transition of System Clock
R/W
R
R
Reset release
RC oscillator operated
RC oscillator halted
Description
External Clock Halt Detection Flag
This bit indicates the checking result of the external clock
state.
0: External oscillation is in use
1: External oscillation is halted.
This bit is meaningless. This bit is always read as 1.
LSI Operating Clock Status
0: This LSI operates on internal RC clock.
1: This LSI operates on external clock.
When OSCBAKE
When OSCBAKE
LSI operates on internal RC clock
LSI operates on external oscillator
1
0
RC oscillator: Operated
External oscillator: Halted
RC oscillator: Operated
External oscillator: Operated
Rev. 1.00, 11/03, page 71 of 376
*
Switching to
external clock