PCI6621 datasheet(56/204 Pages) TI

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3−8

Speaker

Subsystem

BINARY_SPKR

System

Core Logic

PCI6x21/

PCI6x11

CAUDPWM

SPKROUT

PWM_SPKR

Figure 3−4. SPKROUT Connection to Speaker Driver

3.5.9

LED Socket Activity Indicators

The socket activity LEDs are provided to indicate when a PC Card is being accessed. The LEDA1 and LEDA2 signals

can be routed to the multifunction terminals. When configured for LED outputs, these terminals output an active high

signal to indicate socket activity. LEDA1 indicates socket A (card A) activity, and LEDA2 indicates socket B (card B)

activity. The LED_SKT output indicates socket activity to either socket A or socket B. See Section 4.36, Multifunction

Routing Status Register, for details on configuring the multifunction terminals.

The active-high LED signal is driven for 64 ms. When the LED is not being driven high, it is driven to a low state. Either

of the two circuits shown in Figure 3−5 can be implemented to provide LED signaling, and the board designer must

implement the circuit that best fits the application.

The LED activity signals are valid when a card is inserted, powered, and not in reset. For PC Card-16, the LED activity

signals are pulsed when READY(IREQ) is low. For CardBus cards, the LED activity signals are pulsed if CFRAME,

IRDY, or CREQ are active.

PCI6x21/

PCI6x11

Current Limiting

≈ 150 Ω

Socket A

LED

MFUNCx

Current Limiting

≈ 150 Ω

Socket B

LED

MFUNCy

Figure 3−5. Two Sample LED Circuits

As indicated, the LED signals are driven for a period of 64 ms by a counter circuit. To avoid the possibility of the LEDs

appearing to be stuck when the PCI clock is stopped, the LED signaling is cut off when the SUSPEND signal is

asserted, when the PCI clock is to be stopped during the clock run protocol, or when in the D2 or D1 power state.

If any additional socket activity occurs during this counter cycle, then the counter is reset and the LED signal remains

driven. If socket activity is frequent (at least once every 64 ms), then the LED signals remain driven.

3.5.10 CardBus Socket Registers

The PCI6x21/PCI6x11 controller contains all registers for compatibility with the PCI Local Bus Specification and the

PC Card Standard. These registers, which exist as the CardBus socket registers, are listed in Table 3−6.

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