
3
–
4
3.5
PC Card Applications
This section describes the PC Card interfaces of the PCI1520.
Card insertion/removal and recognition
P
2
C power-switch interface
Zoomed video support
Speaker and audio applications
LED socket activity indicators
CardBus socket registers
3.5.1
PC Card Insertion/Removal and Recognition
The
PC Card Standard
(release 7.1) addresses the card-detection and recognition process through an interrogation
procedure that the socket must initiate on card insertion into a cold, nonpowered socket. Through this interrogation,
card voltage requirements and interface (16-bit versus CardBus) are determined.
The scheme uses the card-detect and voltage-sense signals. The configuration of these four terminals identifies the
card type and voltage requirements of the PC Card interface. The encoding scheme is defined in the
PC Card
Standard
(release 7.1) and in Table 3
–
1.
Table 3
–
1. PC Card Card-Detect and Voltage-Sense Connections
CD2//CCD2
Ground
CD1//CCD1
Ground
VS2//CVS2
Open
VS1//CVS1
Open
KEY
5 V
INTERFACE
16-bit PC Card
VOLTAGE
5 V
Ground
Ground
Open
Ground
5 V
16-bit PC Card
5 V and 3.3 V
Ground
Ground
Ground
Ground
5 V
16-bit PC Card
5 V, 3.3 V, and X.X V
Ground
Ground
Open
Ground
LV
16-bit PC Card
3.3 V
Ground
Connect to CVS1
Open
Connect to CCD1
LV
CardBus PC Card
3.3 V
Ground
Ground
Ground
Ground
LV
16-bit PC Card
3.3 V and X.X V
Connect to CVS2
Ground
Connect to CCD2
Ground
LV
CardBus PC Card
3.3 V and X.X V
Connect to CVS1
Ground
Ground
Connect to CCD2
LV
CardBus PC Card
3.3 V, X.X V, and Y.Y V
Ground
Ground
Ground
Open
LV
16-bit PC Card
X.X V
Connect to CVS2
Ground
Connect to CCD2
Open
LV
CardBus PC Card
X.X V
Ground
Connect to CVS2
Connect to CCD1
Open
LV
CardBus PC Card
X.X V and Y.Y V
Connect to CVS1
Ground
Open
Connect to CCD2
LV
CardBus PC Card
Y.Y V
Ground
Connect to CVS1
Ground
Connect to CCD1
Reserved
Ground
Connect to CVS2
Connect to CCD1
Ground
Reserved
3.5.2
P
2
C Power-Switch Interface (TPS222X)
The PCI1520 provides a PCMCIA peripheral control (P
2
C) interface for control of the PC Card power switch. The
CLOCK, DATA, and LATCH terminals interface with the TI TPS222X dual-slot PC Card power interface switches to
provide power switch support. Figure 3
–
3 illustrates a typical application where the PCI1520 represents the PCMCIA
controller. Table 3
–
2 shows the available power switch options compatible with the PCI1520.