PCI7421 datasheet(80/298 Pages) TI

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3−24

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 PCI7x21/PCI7x11 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 PCI7x21/PCI7x11 registers.

3.8.8

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 PCI7x21/PCI7x11 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 3−15 shows various enable bits for the PCI7x21/PCI7x11 RI_OUT function; however, it does not show the

masking of CSC events. See Table 3−10 for a detailed description of CSC interrupt masks and flags.

Card

I/F

PC Card

Socket A

CSC

CSTSMASK

RIENB

RI_OUT

RI_OUT Function

RINGEN

CDRESUME

CSC

PC Card

Socket B

Figure 3−15. RI_OUT Functional Diagram

RI from the 16-bit PC Card interface is masked by bit 7 (RINGEN) in the ExCA interrupt and general control register

(ExCA offset 03h/43h/803h, see Section 5.4). This is programmed on a per-socket basis and is only applicable when

a 16-bit card is powered in the socket.

The CBWAKE signaling to RI_OUT is enabled through the same mask as the CSC event for CSTSCHG. The mask

bit (bit 0, CSTSMASK) is programmed through the socket mask register (CB offset 04h, see Section 6.2) in the

CardBus socket registers.

RI_OUT can be routed through any of three different pins, RI_OUT/PME, MFUNC2, or MFUNC4. The RI_OUT

function is enabled by setting bit 7 (RIENB) in the card control register (PCI offset 91h, see Section 4.38). The PME

function is enabled by setting bit 8 (PME_ENABLE) in the power-management control/status register (PCI offset A4h,

see Section 4.44). When bit 0 (RIMUX) in the system control register (PCI offset 80h, see Section 4.29) is set to 0,

both the RI_OUT function and the PME function are routed to the RI_OUT/PME terminal. If both functions are enabled

and RIMUX is set to 0, then the RI_OUT/PME terminal becomes RI_OUT only and PME assertions are never seen.

Therefore, in a system using both the RI_OUT function and the PME function, RIMUX must be set to 1 and RI_OUT

must be routed to either MFUNC2 or MFUNC4.

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