STMicroelectronics SPC572L series Reference Manual page 494

Clock Monitor Unit (CMU)
Note: An example of determining the HFREF
f
CLKMT0_RMN
the ideal HFREF
into consideration (HFREF
If f
CLKMN1
the CLKMN1 is 'ON' as signaled by the MC_ME, then:
•
The CMU writes 1 to CMU_ISR[FLLI].
•
The CMU asserts the FLL signal.
Note: The low reference value must be programmed considering the following factors
• 2 cycles of f
• Frequency variation % of f
Note: For example, assuming f
f
CLKMN1
tolerances will be 758 (LFREF
Note: The minimum value that can be programmed in CMU_LFREFR[LFREF] is 3. The minimum
frequency that can be monitored using the CLKMN1 supervisor must be >=
f
CLKMT0_RMN
494/2058
= 16 MHz with an accuracy of +/-5%. In order to monitor f
= 800. The actual HFREF value will be 842 when the accuracy is taken
Ideal
Actual
is less than a reference value determined by the bits CMU_LFREFR[LFREF] and
which is the built-in tolerance of the monitor implementation
CLKMN1
CLKMT0_RMN
(200MHz), the ideal LFREF
/16.
value is as follows. Assume a
Actual
= (HFREF + 2) × 1.05).
Ideal
across PVT
CLKMT0_RMN
is 16MHz with +/-5% variation, in order to monitor the
is 800. The adjusted value considering the
Ideal
= (LFREF -2) x 0.95).
Actual Ideal
DocID027809 Rev 4
RM0400
= 200 MHz,
CLKMN1