Texas Instruments Dual/Single Socket CardBus and UntraMedia Controller PCI7621 - Manual (Page 74)

3−18
Table 3−11. PC Card Interrupt Events and Description
CARD TYPE EVENT TYPE SIGNAL DESCRIPTION
Battery conditions
CSC
BVD1(STSCHG)//CSTSCHG
A transition on BVD1 indicates a change in the
PC Card battery conditions.
16-bit
memory
Battery conditions
(BVD1, BVD2)
CSC
BVD2(SPKR)//CAUDIO
A transition on BVD2 indicates a change in the
PC Card battery conditions.
memory
Wait states
(READY)
CSC READY(IREQ)//CINT
A transition on READY indicates a change in the
ability of the memory PC Card to accept or provide
data.
16-bit I/O
Change in card
status (STSCHG)
CSC BVD1(STSCHG)//CSTSCHG
The assertion of STSCHG indicates a status change
on the PC Card.
16-bit I/O/
UltraMedia
Interrupt request
(IREQ)
Functional READY(IREQ)//CINT
The assertion of IREQ indicates an interrupt request
from the PC Card.
CardBus
Change in card
status (CSTSCHG)
CSC BVD1(STSCHG)//CSTSCHG
The assertion of CSTSCHG indicates a status
change on the PC Card.
CardBus
Interrupt request
(CINT)
Functional READY(IREQ)//CINT
The assertion of CINT indicates an interrupt request
from the PC Card.
All PC Cards/
Smart Card
adapters/
Card insertion
or removal
CSC
CD1//CCD1,
CD2//CCD2
A transition on either CD1//CCD1 or CD2//CCD2
indicates an insertion or removal of a 16-bit or
CardBus PC Card.
adapters/
UltraMedia/
Flash Media
Power cycle
complete
CSC N/A
An interrupt is generated when a PC Card power-up
cycle has completed.
The naming convention for PC Card signals describes the function for 16-bit memory, I/O cards, and CardBus. For
example, READY(IREQ)//CINT includes READY for 16-bit memory cards, IREQ for 16-bit I/O cards, and CINT for
CardBus cards. The 16-bit memory card signal name is first, with the I/O card signal name second, enclosed in
parentheses. The CardBus signal name follows after a double slash (//).
The 1997 PC Card Standard describes the power-up sequence that must be followed by the PCI7x21/PCI7x11
controller when an insertion event occurs and the host requests that the socket V
CC
and V
PP
be powered. Upon
completion of this power-up sequence, the PCI7x21/PCI7x11 interrupt scheme can be used to notify the host system
(see Table 3−11), denoted by the power cycle complete event. This interrupt source is considered a PCI7x21/PCI7x11
internal event, because it depends on the completion of applying power to the socket rather than on a signal change
at the PC Card interface.
3.7.2 Interrupt Masks and Flags
Host software may individually mask (or disable) most of the potential interrupt sources listed in Table 3−11 by setting
the appropriate bits in the PCI7x21/PCI7x11 controller. By individually masking the interrupt sources listed, software
can control those events that cause a PCI7x21/PCI7x11 interrupt. Host software has some control over the system
interrupt the PCI7x21/PCI7x11 controller asserts by programming the appropriate routing registers. The
PCI7x21/PCI7x11 controller allows host software to route PC Card CSC and PC Card functional interrupts to separate
system interrupts. Interrupt routing somewhat specific to the interrupt signaling method used is discussed in more
detail in the following sections.
When an interrupt is signaled by the PCI7x21/PCI7x11 controller, the interrupt service routine must determine which
of the events listed in Table 3−10 caused the interrupt. Internal registers in the PCI7x21/PCI7x11 controller provide
flags that report the source of an interrupt. By reading these status bits, the interrupt service routine can determine
the action to be taken.
Table 3−10 details the registers and bits associated with masking and reporting potential interrupts. All interrupts can
be masked except the functional PC Card interrupts, and an interrupt status flag is available for all types of interrupts.
Notice that there is not a mask bit to stop the PCI7x21/PCI7x11 controller from passing PC Card functional interrupts
through to the appropriate interrupt scheme. These interrupts are not valid until the card is properly powered, and
there must never be a card interrupt that does not require service after proper initialization.