Preliminary User’s Manual U16315EJ1V0UD
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CHAPTER 20 CLOCK MONITOR
20.1 Functions of Clock Monitor
The clock monitor samples the X1 input clock using the on-chip Ring-OSC, and generates an internal reset signal
when the X1 input clock is stopped.
When a reset signal is generated by the clock monitor, bit 1 (CLMRF) of the reset control flag register (RESF) is set
to 1. For details of RESF, refer to
CHAPTER 19 RESET FUNCTION
.
The clock monitor automatically stops under the following conditions.
•
In STOP mode and during the oscillation stabilization time
•
When the X1 input clock is stopped by software (when MSTOP = 1 or MCC = 1)
•
During the oscillation stabilization time after reset is released
•
When the Ring-OSC clock is stopped
Remark
MSTOP: Bit 7 of the main OSC control register (MOC)
20.2 Configuration of Clock Monitor
Clock monitor consists of the following hardware.
Table 20-1. Configuration of Clock Monitor
Item
Configuration
Control register
Clock monitor mode register (CLM)
Figure 20-1. Block Diagram of Clock Monitor
X1 input clock
Ring-OSC clock
Internal reset signal
Enable/disable
CLME
Clock monitor mode register (CLM)