Clocks
Copyright © 2002 Marvell
CONFIDENTIAL
Doc. No. MV-S300165-00, Rev. A
May 21, 2002, Preliminary
Document Classification: Proprietary Information
Page 143
Section 19. Clocks
The GT-64260A device implements several clock domains:
•
TClk is the internal source clock. If AD[5] is pulled HIGH at reset de-assertion, TClk is also used as the clock
source for the CPU interface.
•
SysClk functionality is configured at reset. If AD[5] is pulled LOW at reset, SysClk is used as the clock source
for the CPU interface, running asynchronously to TClk.
•
PClk0 is the clock source for PCI0 interface.
•
PClk1 is the clock source for PCI1 interface.
•
SDClkIn/Out.
Note
For the SDRAM clocking scheme, it is not recommended to use the SDClkOut configuration. For more
information on the SDRAM interface clocking, see the GT-64260A datasheet and
AN- 82: SDRAM
Clocking Schemes in the GT-642xx/A Devices
on the secure website.
•
BClkIn can be used as a clock input to the baud rate generator. It is multiplexed on the MPP interface. See
Section 8. "Multi-Purpose Pin Interface Functional Overview" on page 74
•
BClkOut can be used as a clock output from the baud rate generator. It is multiplexed on the MPP interface.
See
Section 8. "Multi-Purpose Pin Interface Functional Overview" on page 74
Notes
•
For more information on the GT-64260A clocks, see the GT-64260A datasheet’s "GT-64260A Clocking"
section.
•
The maximum allowed jitter on the TClk clock input is +/-100 pS.