PCI1225PDV datasheet(42/131 Pages) TI

42 / 131 page

PCI1225 GHK/PDV

PC CARD CONTROLLERS

SCPS035B – MAY 1998 – REVISED – MAY 2000

POST OFFICE BOX 655303

• DALLAS, TEXAS 75265

suspend mode

The SUSPEND signal provides backward compatibility and gates the PCI reset (PRST) signal from the

PCI1225. However, additional functionality has been defined for SUSPEND to provide additional

power-management options.

SUSPEND provides a mechanism to gate PCLK from the PCI1225, as well as gate PRST. This can potentially

save power while in an idle state; however, it requires substantial design effort to implement. Some issues to

consider are:

D What if cards are present in the sockets?

D What if the cards in the sockets are powered?

D How to pass CSC (insertion/removal) events.

Even without the PCI clock to the PCI1225 core, asynchronous-type functions (such as RI_OUT) can pass CSC

events, wake-up events, etc., back to the system. If a system designer chooses to not pass card removal events

through to the system, then the PCI1225 would not be able to power down the empty socket without the power

switch clock (CLOCK) generated externally. See the P2C power switch interface for details. Figure 17 is a

functional implementation diagram.

PCI1225

Core

SUSPEND

PRST

GNT

PCLK

Figure 17. SUSPEND Functional Implementation

Figure 18 is a signal diagram of the suspend function.

PCI1225PDV Datasheet(PDF) 42 Page - Texas Instruments