
Principles of Operation
66
September 2005
SCPS110
3.8.7 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 PCIxx12 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 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 PCIxx12 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 PCIxx12 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 315 shows various enable bits for the PCIxx12 RI_OUT function; however, it does not show the
masking of CSC events. See Table 310 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
RI
Figure 315. 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/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 4.37). The
PME function is enabled by setting bit 8 (PME_ENABLE) in the power-management control/status register
(PCI offset A4h, see Section 4.43). When bit 0 (RIMUX) in the system control register (PCI offset 80h, see
Section 4.29) is set to 0b, both the RI_OUT function and the PME function are routed to the RI_OUT/PME
terminal. Therefore, in a system using both the RI_OUT function and the PME function, RIMUX must be set
to 1b and RI_OUT must be routed to either MFUNC2 or MFUNC4.