Datasheet

3−19
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 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 3−16 shows various enable bits for the RI_OUT
function; however, it does not show the masking of CSC
events. See Table 3−7 for a detailed description of CSC interrupt masks and flags.
Card
I/F
PC Card
Socket
CSTSMASK
RIENB
RI_OUT
RI_OUT Function
RINGEN
CDRESUME
Figure 3−16. 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 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 RIENB in the card control register (PCI offset 91h, see Section 4.32). The PME function
is enabled by setting PMEEN in the power management control/status register (PCI offset A4h, see Section 4.38).
When 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. If both functions are enabled and RIMUX is set to 0b,
the RI_OUT
/PME terminal becomes RI_OUT only and PME assertions will never be seen. 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.
3.8.8 PCI Power Management
The PCI Bus Power Management Interface Specification for PCI to CardBus Bridges establishes the infrastructure
required to let the operating system control the power of PCI functions. This is done by defining a standard PCI
interface and operations to manage the power of PCI functions on the bus. The PCI bus and the PCI functions can
be assigned one of seven power-management states, resulting in varying levels of power savings.
The seven power-management states of PCI functions are:
• D0-uninitialized − Before device configuration, device not fully functional
• D0-active − Fully functional state
• D1 − Low-power state
• D2 − Low-power state