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Note: When CSS is activated by software and HSECLK fails, CSS interrupt and NMI (non-maskable
interrupt) will be generated. Since NMI is executed continuously before CSS interrupt is cleared,
CSSCLR bit in RCM_INT register shall be set to clear the interrupt.
TMR5-based internal/external clock measurement
Through the input capture function of TMR5 Channel 4, the frequency of certain
clock source generators can be indirectly measured. The circuit diagram is as
follows:
Figure 7 TMR5 Measurement Clock Frequency Circuit Diagram
TMR5
GPIO
RTC_Wakeup_IT
LSECLK
LSICLK
RMPSEL
TI4
Channel 4 of TMR5 can select to connect one GPIO port or one MCU internal
clock by configuring RMPSEL bit of TMR5_OPT register
TMR11-based internal/external clock measurement
The external oscillator frequency can be tested through TMR11 when HSICLK is
used as the system clock source. As shown in the figure below, the user can
select to trigger TI1 by I/O port or internal clock by configuring the RMPSEL bit
of TMR11_OPT register.
Figure 8 TMR11 Measurement Clock Frequency Circuit Diagram
TMR11
GPIO
HSECLK_RTC
RMPSEL
TI1
Register address mapping
Table 35 RCM Register Address Mapping
Register name
Description
Offset address
RCM_CTRL
Clock control register
0x00