Clock and Board Guidelines
MPC561/MPC563 Reference Manual, Rev. 1.2
Freescale Semiconductor
C-7
MF is the multiplication factor in the PLPRCR register (refer to
Section 8.11.2, “PLL, Low-Power, and
Reset-Control Register (PLPRCR)
” for more information).
Figure C-8. PLL Off-Chip Capacitor Example
C.3
PLL and Clock Oscillator External Components Layout
Requirements
C.3.1
Traces and Placement
Traces connecting capacitors, crystal, resistor should be as short as possible. Therefore, the components
(crystal, resistor and capacitors) should be placed as close to the oscillator pins of the MPC561/MPC563
as possible.
The voltage to the VDDSYN pin should be well regulated and the pin should be provided with an
extremely low impedance path from the VDDSYN filter to the VDDSYN pad.
The VSSSYN pin should be provided with an extremely low impedance path in the board. All the filters
for the supplies should be located as close as possible to the chip package. It is recommended to design
individual VSSSYN plane to improve VSSSYN quietness.
C.3.2
Grounding/Guarding
The traces from the oscillator pins and PLL pins of the MPC561/MPC563 should be guarded from all other
traces to reduce crosstalk. It can be provided by keeping other traces away from the oscillator circuit and
placing a ground plane around the components and traces.
C.3.3
IRAMSTBY Regulator Circuit
IRAMSTBY is the data retention power supply for all on-board RAM arrays (CALRAM, DPTRAM,
DECRAM). It has a shunt regulator circuit to divert excess current to ground in order to regulate voltage
on the IRAMSTBY power supply pin. IRAMSTBY should be connected to a positive power supply, via a
resistor, and bypassed by a capacitor to ground as shown in
.
XFC
CXFC
VDDSYN
Board
MPC56x Device
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...