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R01UH0336EJ0102 Rev.1.02
Page 270 of 1538
Jul 17, 2014
V850E2/PG4-L
Section 7 Clock Generation
7.8.2
CLMA Enable and Start-Up Options
(1)
CLMA Enable
Monitoring of clock signals by a clock monitor is set up by setting the
CLMAnCTL1, CLMAnCMPL, and CLMAnCMPH registers, and starts when the
CLMAnCLME bit in the CLMAnCTL0 register is set to 1.
7.8.3
Functional Overview
The clock monitor CLMAn indicates an abnormal frequency of the monitored
clock.
Features
summary
The clock monitor has the following features:
• monitoring of the frequency of an input clock CLMAnTMON by using a
sampling clock CLMAnTSMP
• indication of abnormal clock frequencies by the following means:
– output of a reset request signal, or
– output of an error signal in combination with the generation of an error
interrupt request
The following figure shows the main components of the clock monitor.
Figure 7-2
Block Diagram of the Clock Monitor A
Note
Abnormalities cannot be detected while the sampling clock is stopped. It is
recommended to use CLM0 to CLM2 for mutual monitoring.
CLMAnTI
CLMAnTSMP
CLMAnTMON
CLMAnTERR
CLMAnRES
CLMAnCMPH
CLMAnCMPL
CLMAnCTL0
CLMAnCTL1
Internal bus
Internal bus
12-bit counter
Timer
Upper limit
Frequency
violation
Output
control
Match
Lower limit