The Clock Module - Freescale Semiconductor MPC850 User Manual

The Clock Module

EXTCLK
XTAL
Main Clock
Oscillator
(OSCM)
EXTAL
Note that only CLKOUT is an actual external output; all other outputs are internal signals.
14.2 The Clock Module
The clock module consists of two external reference sources and a programmable
phase-locked loop, arranged as shown in Figure 14-2.
MODCK[1:2]
2:1
MUX
oscclk
2:1 MUX
(÷4 OR ÷16)
tbclk
SCCR[RTSEL]
2:1
MUX
Figure 14-1. Clock Source and Distribution
MPC850 Family User's Manual
XFC V DDSYN
SPLL
vcoout
SCCR
[TBS]
Low-Power
CLKOUT
Time Base and
Decrementer
SCCR[RTDIV]
÷4
2:1
MUX
and Driver
÷512
gclk2
gclk/
gclk2
gclk1c/
gclk2c
Dividers
gclk1_50/
gclk2_50
Clock
Drivers
brgclk
syncclk
CLKOUT
Driver
tmbclk
Driver
RTC/PIT
Clock
pitrtclk