Clocks and Power Control
MPC561/MPC563 Reference Manual, Rev. 1.2
Freescale Semiconductor
8-7
The low-power divider block is controlled in the system clock control register (SCCR). The default state
of the low-power divider is to divide all clocks by one. Thus, for a 40-MHz system, the general system
clocks are each 40 MHz. Whenever power-on reset is asserted, the MF bits are set according to
and the division factor high frequency (DFNH) and division factor low frequency (DFNL) bits in SCCR
are set to the value of 0 (
÷
1 for DFNH and
÷
2 for DFNL).
8.5
Internal Clock Signals
The internal clocks generated by the clocks module are shown in
. The clocks module also
generates the CLKOUT and ENGCLK external clock signals. The PLL synchronizes these signals to each
other. The PITRTCLK frequency and source are specified by the RTDIV and RTSEL bits in the SCCR.
When the backup clock is functioning as the system clock, the backup clock is automatically selected as
the time base clock source and is twice the MPC561/MPC563 system clock.
Summary of Contents for MPC561
Page 84: ...MPC561 MPC563 Reference Manual Rev 1 2 lxxxiv Freescale Semiconductor...
Page 144: ...Signal Descriptions MPC561 MPC563 Reference Manual Rev 1 2 2 46 Freescale Semiconductor...
Page 206: ...Central Processing Unit MPC561 MPC563 Reference Manual Rev 1 2 3 62 Freescale Semiconductor...
Page 302: ...Reset MPC561 MPC563 Reference Manual Rev 1 2 7 14 Freescale Semiconductor...
Page 854: ...Time Processor Unit 3 MPC561 MPC563 Reference Manual Rev 1 2 19 24 Freescale Semiconductor...
Page 968: ...Development Support MPC561 MPC563 Reference Manual Rev 1 2 23 54 Freescale Semiconductor...
Page 1144: ...Internal Memory Map MPC561 MPC563 Reference Manual Rev 1 2 B 34 Freescale Semiconductor...
Page 1212: ...TPU3 ROM Functions MPC561 MPC563 Reference Manual Rev 1 2 D 60 Freescale Semiconductor...
Page 1216: ...Memory Access Timing MPC561 MPC563 Reference Manual Rev 1 2 E 4 Freescale Semiconductor...