PCI6421 datasheet(70/204 Pages) TI

70 / 204 page

3−22

RESET

GNT

SUSPEND

PCLK

RESETIN

SUSPENDIN

PCLKIN

External Terminals

Internal Signals

Figure 3−13. Signal Diagram of Suspend Function

3.8.6

Requirements for Suspend Mode

The suspend mode prevents the clearing of all register contents on the assertion of reset (PRST or GRST) which

would require the reconfiguration of the PCI6x21/PCI6x11 controller by software. Asserting the SUSPEND signal

places the PCI outputs of the controller in a high-impedance state and gates the PCLK signal internally to the

controller unless a PCI transaction is currently in process (GNT is asserted). It is important that the PCI bus not be

parked on the PCI6x21/PCI6x11 controller when SUSPEND is asserted because the outputs are in a high-impedance

state.

The GPIOs, MFUNC signals, and RI_OUT signal are all active during SUSPEND, unless they are disabled in the

appropriate PCI6x21/PCI6x11 registers.

3.8.7

Ring Indicate

The RI_OUT output is an important feature in power management, allowing a system to go into a suspended mode

and wake-up on modem rings and other card events. TI-designed flexibility permits this signal to fit wide platform

requirements. RI_OUT on the PCI6x21/PCI6x11 controller can be asserted under any of the following conditions:

•

A 16-bit PC Card modem in a powered socket asserts RI to indicate to the system the presence of an

incoming call.

•

A powered down CardBus card asserts CSTSCHG (CBWAKE) requesting system and interface wake-up.

•

A powered CardBus card asserts CSTSCHG from the insertion/removal of cards or change in battery

voltage levels.

Figure 3−14 shows various enable bits for the PCI6x21/PCI6x11 RI_OUT function; however, it does not show the

masking of CSC events. See Table 3−9 for a detailed description of CSC interrupt masks and flags.

PCI6421 Datasheet(PDF) 70 Page - Texas Instruments