PXS20RM Datasheet, PDF (244/1368 Pages) Freescale Semiconductor, Inc – PXS20 Microcontroller

Clock Monitor Unit (CMU)
• A failure event FLC is signaled to the MC_RGM and FCCU, which in turn can generate a
‘functional’ reset, a SAFE mode request, or an interrupt.
If F_{MOTC_CLK} is less than a reference value determined by the CMU_LFREFR_A[LFREF_A] bits and the
currently selected motor control clock source is ‘ON’ (and locked in the case of FMPLL_0 or FMPLL_1),
then:
• CMU_ISR[FLLI] is set.
• A failure event is signaled to the MC_RGM and FCCU, which in turn can generate a ‘functional’
reset, a SAFE mode request, or an interrupt.
NOTE
The motor control clock monitor may produce a false event when
F_{MOTC_CLK} is less than 2F_{IRCOSC_CLK}2_{CMU_CSR[RCDIV]} due to an
accuracy limitation of the compare circuitry.
12.4.1.3 FlexRay clock monitor
The FlexRay clock is monitored by CMU_2. F_{FR_CLK} can be monitored by programming
CMU_CSR[CME] = 1. FR_CLK monitoring starts as soon as CMU_CSR[CME] = 1. This monitor can be
disabled at any time by programming CMU_CSR[CME] = 0.
If F_{FR_CLK} is greater than a reference value determined by the CMU_HFREFR_A[HFREF_A] bits and
the currently selected motor control clock source is ‘ON’ and locked, then
• CMU_ISR[FHHI] is set.
• failure event is signaled to the MC_RGM and FCCU, which in turn can generate a ‘functional’
reset, a SAFE mode request, or an interrupt.
If F_{FR_CLK} is less than a reference clock frequency (F_{IRCOSC_CLK}4) and the currently selected motor
control clock source is ‘ON’ and locked, then:
• CMU_ISR[FLCI] is set.
• A failure event FLC is signaled to the MC_RGM and FCCU, which in turn can generate a
‘functional’ reset, a SAFE mode request, or an interrupt.
If F_{FR_CLK} is less than a reference value determined by the CMU_LFREFR_A[LFREF_A] bits and the
currently selected motor control clock source is ‘ON’ locked, then:
• CMU_ISR[FLLI] is set.
• A failure event is signaled to the MC_RGM and FCCU, which in turn can generate a ‘functional’
reset, a SAFE mode request, or an interrupt.
NOTE
TthhaenF2l_exFR_IRa_Cy_Oc_Sl_Co_{_}c_Ck_Lm_Ko_n2i_Cto_Mr_Um_{_C}ay_SRp_[r_Ro_Cd_Du_Ic_Ve_]adfuaelsteoeavnenact _{cwuhraecnyFlFiRm_iCtaLtKioins}
less
of
the compare circuitry.
12-8
PXS20 Microcontroller Reference Manual, Rev. 1
Freescale Semiconductor