MPC8309EC datasheet(68/82 Pages) FREESCALE

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MPC8309 PowerQUICC II Pro Integrated Communications Processor Family Hardware Specifications, Rev. 0

Freescale Semiconductor

Clocking

Configuration chapter in the MPC8309 PowerQUICC II Pro Communications Processor Reference

Manual.

The qe_clk frequency is determined by the QUICC Engine PLL multiplication factor (RCWL[CEPMF])

and the QUICC Engine PLL division factor (RCWL[CEPDF]) as the following equation:

qe_clk = (QE_CLK_IN × CEPMF)

 (1 + CEPDF)

Eqn. 3

For more information, see the QUICC Engine PLL Multiplication Factor section and the “QUICC Engine

PLL Division Factor” section in the MPC8309 PowerQUICC II Pro Communications Processor

Reference Manual for more information.

The DDR SDRAM memory controller operates with a frequency equal to twice the frequency of csb_clk.

Note that ddr_clk is not the external memory bus frequency; ddr_clk passes through the DDR clock divider

(

2) to create the differential DDR memory bus clock outputs (MCK and MCK). However, the data rate

is the same frequency as ddr_clk.

The local bus memory controller operates with a frequency equal to the frequency of csb_clk. Note that

lbc_clk is not the external local bus frequency; lbc_clk passes through the LBC clock divider to create the

external local bus clock outputs (LCLK). The LBC clock divider ratio is controlled by LCCR[CLKDIV].

For more information, see the LBC Bus Clock and Clock Ratios section in the MPC8309 PowerQUICC

II Pro Communications Processor Reference Manual.

In addition, some of the internal units may be required to be shut off or operate at lower frequency than

the csb_clk frequency. These units have a default clock ratio that can be configured by a memory mapped

Table 56 specifies which units have a configurable clock frequency. For detailed description, refer to the

“System Clock Control Register (SCCR)” section in the MPC8309 PowerQUICC II Pro Communications

Processor Reference Manual.

NOTE

Setting the clock ratio of these units must be performed prior to any access

to them.

Table 57 provides the maximum operating frequencies for the MPC8309 MAPBGA under recommended

operating conditions (see Table 2).

Table 56. Configurable Clock Units

Unit

Default Frequency

Options

I2C,SDHC, USB, DMA Complex

csb_clk

Off, csb_clk, csb_clk/2, csb_clk/3

Table 57. Operating Frequencies for MAPBGA

Characteristic1

Max Operating Frequency

Unit

e300 core frequency (core_clk)417

MHz

Coherent system bus frequency (csb_clk)167

MHz

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