Clocking
15 Clocking
This section describes the PLL configuration of the MPC8540. Note that the platform clock is identical to
the CCB clock.
15.1 Clock Ranges
Table 54 provides the clocking specifications for the processor core and Table 55 provides the clocking
specifications for the memory bus.
Table 54. Processor Core Clocking Specifications
Maximum Processor Core Frequency
Characteristic
667 MHz
833 MHz
1 GHz
Unit
Notes
Min
400
Max
Min
400
Max
Min
Max
e500 core processor frequency
667
833
400
1000
MHz
1, 2, 3
Notes:
1.Caution: The CCB to SYSCLK ratio and e500 core to CCB ratio settings must be chosen such that the resulting SYSCLK
frequency, e500 (core) frequency, and CCB frequency do not exceed their respective maximum or minimum operating
frequencies. Refer to Section 15.2, “Platform/System PLL Ratio,” and Section 15.3, “e500 Core PLL Ratio,” for ratio
settings.
2.)The minimum e500 core frequency is based on the minimum platform frequency of 200 MHz.
3.)The 1.0 GHz core frequency is based on a 1.3 V VDD supply voltage.
Table 55. Memory Bus Clocking Specifications
Maximum Processor Core Frequency
Characteristic
667 MHz
833 MHz
1 GHz
Unit
Notes
Min
100
Max
Min
100
Max
Min
Max
Memory bus frequency
166
166
100
166
MHz
1, 2, 3
Notes:
1.Caution: The CCB to SYSCLK ratio and e500 core to CCB ratio settings must be chosen such that the resulting SYSCLK
frequency, e500 (core) frequency, and CCB frequency do not exceed their respective maximum or minimum operating
frequencies. Refer to Section 15.2, “Platform/System PLL Ratio,” and Section 15.3, “e500 Core PLL Ratio,” for ratio
settings.
2.The memory bus speed is half of the DDR data rate, hence, half of the platform clock frequency.
3.)The 1.0 GHz core frequency is based on a 1.3 V VDD supply voltage.
MPC8540 Integrated Processor Hardware Specifications, Rev. 4
76
Freescale Semiconductor
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