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MVME2500 Installation and Use (6806800L01H)
121
7.7 Clock Distribution
The clock function generates and distributes all of the clocks required for system operation.
The ICS9FG108 is used to generate all the required PCI-E clocks. The 25 MHz clocks for the
Ethernet PHY and SATA bridge are supplied by ICS83905. Most of the QorIQ P2020 clocks are
generated by ICS840S07I chip. Additional clocks required by individual devices are generated
near the devices using individual oscillators. The following table lists the clocks required on the
MVME2500 along with the frequency and source.
SETA External address termination
0 - Access is terminated internally by the memory controller unless the
external device asserts LGTA earlier to terminate the access.
TRLX Timing Relaxed
0 - Normal timing is generated by the GPCM.
EHTR Extended hold time on read accesses.
0 - The memory controller generates normal timing. No additional cycles
are inserted
EAD External address latch delay
0 - No additional bus clock cycles (LALE asserted for one bus clock cycle
only)
Table 7-6 Clock Distribution
Device Clock Signal Frequency Clock Tree Source VIO
QorIQ P20x0 CPU_SYSCLK 100MHz ICS840S07I +3.3V
QorIQ P20x0 CPU_DDR_CLK 100MHz ICS840S07I +3.3V
QorIQ P20x0 CLK_PCI_BR3 133Mhz ICS840S07I +3.3V
QorIQ P20x0 EC_GTX_CLK125 125Mhz ICS840S07I +3.3V
ICS840S07I CLK_25MHZ_ICS840S07 25Mhz ICS83905AGILF +3.3V
88SE6121 CLK_88SE6121_25MHZ 25Mhz ICS83905AGILF +3.3V
ICS9FG108 CLK_25MHZ_ICS9FG108 25Mhz ICS83905AGILF +3.3V
BCM54616S BP_PHY_25MHZ_CLK 25Mhz ICS83905AGILF +3.3V
BCM54616S FP_PHY_25MHZ_CLK 25Mhz ICS83905AGILF +3.3V