Clocks and Power Control
MPC561/MPC563 Reference Manual, Rev. 1.2
8-10
Freescale Semiconductor
NOTE
The reset value of the PLL pre-divider is one.
The values of the PITRTCLK clock division and TMBCLK clock division can be changed by software.
The RTDIV bit value in the SCCR register defines the division of PITRTCLK. All possible combinations
of the TMBCLK divisions are listed in
8.5.1
General System Clocks
The general system clocks (GCLK1C, GCLK2C, GCLK1, GCLK2, GCLK1_50, and GCLK2_50) are the
basic clock supplied to all modules and sub-modules on the MPC561/MPC563. GCLK1C and GCLK2C
are supplied to the RCPU and to the BBC. GCLK1C and GCLK2C are stopped when the chip enters the
doze-low power mode. GCLK1 and GCLK2 are supplied to the SIU and the clock module. The external
bus clock GCLK2_50 is the same as CLKOUT. The general system clock defaults to VCO/2 = 20 MHz
(assuming a 20-MHz system frequency) with default power-on reset MF values.
100
101
0
1
1
1
256
16
Normal operation, PLL enabled.
1:1 Mode
Main timing reference is EXT-
CLK pin (>15MHz)
Limp mode disabled.
110
0
1
1
5
256
4
Normal operation, PLL enabled.
Main timing reference is EXT-
CLK (3-5 MHz).
Limp mode disabled.
111
1
1
1
1
256
16
Normal operation, PLL enabled.
1:1 Mode
Main timing reference is EXT-
CLK pin (>15MHz)
Limp mode enabled.
1
indicates MODCK pins value during power-on reset
Table 8-2. TMBCLK Divisions
1
1
To ensure correct operation of the time base, keep the system clock to time
base clock ratio above 4 and always set SCCR[TBS] = 1 when running on
the backup clock (limp mode).
SCCR[TBS]
MF + 1
TMBCLK
Division
1
—
16
0
1, 2
16
0
> 2
4
Table 8-1. Reset Clocks Source Configuration (continued)
MODCK[1:3]
1
Default Values after
PORESET
SPLL Options
LME
RTSEL
RTDIV
MF + 1
PITCLK
Division
TMBCLK
Division
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...