MPC8358 FREESCALE [Freescale Semiconductor, Inc], MPC8358 Datasheet - Page 75

• Manufacturer Part Number: MPC8358
• Manufacturer: FREESCALE [Freescale Semiconductor, Inc]

parameters select whether CLKIN or CLKIN/2 is driven out on the PCI_CLK_OUTn signals.The
OCCR[PCIOENn] parameters enable the PCI_CLK_OUTn respectively.
PCI_SYNC_OUT is connected externally to PCI_SYNC_IN to allow the internal clock subystem to
synchronize to the system PCI clocks. PCI_SYNC_OUT must be connected properly to PCI_SYNC_IN,
with equal delay to all PCI agent devices in the system, to allow the device to function. When the device
is configured as a PCI agent device, PCI_CLK is the primary input clock. When the device is configured
as a PCI agent device the CLKIN and the CFG_CLKIN_DIV signals should be tied to GND.
When the device is configured as a PCI host device (RCWH[PCIHOST] = 1) and PCI clock output is
disabled (RCWH[PCICKEN] = 0), clock distribution and balancing done externally on the board.
Therefore, PCI_SYNC_IN is the primary input clock.
As shown in , the primary clock input (frequency) is multiplied by the QUICC Engine block phase-locked
loop (PLL), the system PLL, and the clock unit to create the QUICC Engine clock (ce_clk), the coherent
system bus clock (csb_clk), the internal DDRC1 controller clock (ddr1_clk), and the internal clock for the
local bus interface unit and DDR2 memory controller (lb_clk).
The csb_clk frequency is derived from a complex set of factors that can be simplified into the following
equation:
In PCI host mode, PCI_SYNC_IN × (1 + CFG_CLKIN_DIV) is the CLKIN frequency; in PCI agent
mode, CFG_CLKIN_DIV must be pulled down (low), so PCI_SYNC_IN × (1 + CFG_CLKIN_DIV) is
the PCI_CLK frequency.
The csb_clk serves as the clock input to the e300 core. A second PLL inside the e300 core multiplies up
the csb_clk frequency to create the internal clock for the e300 core (core_clk). The system and core PLL
multipliers are selected by the SPMF and COREPLL fields in the reset configuration word low (RCWL)
which is loaded at power-on reset or by one of the hard-coded reset options. See Chapter 4, “Reset,
Clocking, and Initialization,” in the MPC8360E Integrated Communications Processor Reference
Manual, Rev. 2 for more information on the clock subsystem.
The ce_clk frequency is determined by the QUICC Engine PLL multiplication factor (RCWL[CEPMF)
and the QUICC Engine PLL division factor (RCWL[CEPDF]) according to the following equation:
The internal ddr1_clk frequency is determined by the following equation:
Note that the lb_clk clock frequency (for DDRC2) is determined by RCWL[LBCM]. The internal
ddr1_clk frequency is not the external memory bus frequency; ddr1_clk passes through the DDRC1 clock
divider (÷2) to create the differential DDRC1 memory bus clock outputs (MEMC1_MCK and
MEMC1_MCK). However, the data rate is the same frequency as ddr1_clk.
The internal lb_clk frequency is determined by the following equation:
Freescale Semiconductor
MPC8358E PowerQUICC™ II Pro Processor Revision 2.1 PBGA Silicon Hardware Specifications, Rev. 1
csb_clk = {PCI_SYNC_IN × (1 + CFG_CLKIN_DIV)} × SPMF
ce_clk = (primary clock input × CEPMF) ÷ (1 + CEPDF)
ddr1_clk = csb_clk × (1 + RCWL[DDR1CM])
lb_clk = csb_clk × (1 + RCWL[LBCM])
Clocking
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