mpc8308 Freescale Semiconductor, Inc, mpc8308 Datasheet - Page 75

• Manufacturer Part Number: mpc8308
• Description: Mpc8308 Powerquicc Ii Pro Processor Hardware Specification
• Manufacturer: Freescale Semiconductor, Inc

21 Clocking
Figure 53
1
2
The following external clock sources are utilized on the MPC8308:
All clock inputs can be supplied using an external canned oscillator, a clock generation chip, or some other
source that provides a standard CMOS square wave input.
Freescale Semiconductor
Multiplication factor M = 1, 1.5, 2, 2.5, and 3. Value is decided by RCWLR[COREPLL].
Multiplication factor L = 2, 3, 4, 5 and 6. Value is decided by RCWLR[SPMF].
•
•
•
•
SYS_CLK_IN
24–66 MHz
SD_REF_CLK_B
SD_REF_CLK
125/100 MHz
System clock (SYS_CLK_IN)
Ethernet Clock (TSEC1_RX_CLK/TSEC1_TX_CLK/TSEC1_GTX_CLK125 for eTSEC)
SerDes PHY clock
eSHDC clock (SD_CLK)
For more information, see the SerDes chapter in the MPC8308 PowerQUICC II Pro Processor
Reference Manual.
SD_CLK
shows the internal distribution of clocks within the device.
MPC8308 PowerQUICC II Pro Processor Hardware Specification, Rev. 1
+
-
eSHDC
PLL
MPC8308
Figure 53. MPC8308 Clock Subsystem
PCVTR Mux
SerDes PHY
PCI Express
Converter
Protocol
x L
ref
System
PLL
2
fb
Gen
Clk
clk tree
x M
1
e300
PLL
e300 Core
ddr_clk
eTSEC1
lbc_clk
csb_clk
DDR
/n
Clock
Divider
LBC
Clock
Divider
/2
MCK[0:2]
TSEC1_TX_CLK/
TSEC1_GTX_CLK125
TSEC1_RX_CLK
MCK[0:2]
Local
Bus
Memory
Device
DDR
Memory
Device
Clocking
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