PXD10RM Datasheet, PDF (220/1332 Pages) Freescale Semiconductor, Inc – PXD10 Microcontroller

8.10.3 Block diagram
CK_FIRC
CK_SIRC
CK_SXOSC
CK_FIRC
CK_FXOSC
CKSEL1[1:0] CMU_MDR Register
00
01
10
11
MUX 1
Frequency Meter
CMU_FDR
register
Fixed
Prescaler
/4
ckpll_a
FXOSC Supervisor
FOSC < FRC_fast / n
CMU_HREF Register
FPLL > href or
FPLL < FRC_fast / 4
FPLL < lfref
OLR_evt
FXOSC ON/OFF
From MC_ME
FLC_evt_a
FHH_evt_a
PLL ON/OFF
From MC_ME
FLL_evt_a
CMU_LFREF register
PLL Supervisor
Figure 8-25. Clock Monitor Unit diagram
8.10.4 Functional description
The names of the clocks involved in this block have the following meaning:
• CK_FXOSC : clock coming from the external crystal oscillator.
• CK_SIRC: clock coming from the low frequency internal RC oscillator.
• CK_FIRC: clock coming from the high frequency internal RC oscillator.
• CK_PLL : clock coming from the PLL.
• FOSC : frequency of external crystal oscillator clock.
• FRCslow: frequency of low frequency internal RC oscillator.
• FRCfast: frequency of high frequency internal RC oscillator.
• FPLL : frequency of FMPLL clock.
8-42
PXD10 Microcontroller Reference Manual, Rev. 1
Preliminary—Subject to Change Without Notice
Freescale Semiconductor