LPC47N237-MD SMSC [SMSC Corporation], LPC47N237-MD Datasheet - Page 74

• Manufacturer Part Number: LPC47N237-MD
• Description: 3.3V I/O CONTROLLER FOR PORT REPLICATORS AND DOCKING STATIONS
• Manufacturer: SMSC [SMSC Corporation]

Note 12.3
Note 12.4
Revision 0.3 (10-26-04)
SIRQ_CLKRUN_EN
ANY IRQ CHANGE/
DRQ ASSERTION
The signal “ANY IRQ CHANGE/DRQ ASSERTION” is the same as “CHANGE/ASSERTION” in Table
12.1.
The LPC47N237 continually monitors the state of nCLKRUN to maintain the PCI Clock until an active
“ANY IRQ CHANGE/DRQ ASSERTION” condition has been transferred to the host in a SER_IRQ/DMA
cycle. For example, if “ANY IRQ CHANGE/DRQ ASSERTION” is asserted before nCLKRUN is de-
asserted (not shown in Figure 12.2), the LPC47N237 will assert nCLKRUN as needed until the
SER_IRQ/DMA cycle has completed.
nCLKRUN
PCI_CLK
1,2
Figure 12.2 – Clock Start Illustration
DATASHEET
2 CLKS MIN.
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3.3v I/O Controller for Port Replicators and Docking Stations
DRIVEN BY
nCLKRUN
SMSC SIO
SMSC DS – LPC47N237
SMSC SIO
STOPS
DRIVING
nCLKRUN