PCI6621 datasheet(55/204 Pages) TI

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3−7

Table 3−4. TPS2226 Control Logic—xVPP

AVPP CONTROL SIGNALS

OUTPUT

V_AVPP

BVPP CONTROL SIGNALS

OUTPUT

V_BVPP

D8(SHDN)

OUTPUT

V_AVPP

D8(SHDN)

D10

OUTPUT

V_BVPP

0 V

3.3 V

5 V

12 V

Hi-Z

Table 3−5. TPS2226 Control Logic—xVCC

AVCC CONTROL SIGNALS

OUTPUT

V_AVCC

BVCC CONTROL SIGNALS

OUTPUT

V_BVCC

D8(SHDN)

OUTPUT

V_AVCC

D8(SHDN)

OUTPUT

V_BVCC

0 V

3.3 V

5 V

0 V

Hi-Z

3.5.6

Internal Ring Oscillator

The internal ring oscillator provides an internal clock source for the PCI6x21/PCI6x11 controller so that neither the

PCI clock nor an external clock is required in order for the PCI6x21/PCI6x11 controller to power down a socket or

interrogate a PC Card. This internal oscillator, operating nominally at 16 kHz, is always enabled.

3.5.7

Integrated Pullup Resistors for PC Card Interface

The PC Card Standard requires pullup resistors on various terminals to support both CardBus and 16-bit PC Card

configurations. The PCI6x21/PCI6x11 controller has integrated all of these pullup resistors and requires no additional

external components. The I/O buffer on the BVD1(STSCHG)/CSTSCHG terminal has the capability to switch to an

internal pullup resistor when a 16-bit PC Card is inserted, or switch to an internal pulldown resistor when a CardBus

card is inserted. This prevents inadvertent CSTSCHG events. The pullup resistor requirements for the various

UltraMedia interfaces are either included in the UltraMedia cards (or the UltraMedia adapter) or are part of the existing

PCMCIA architecture. The PCI6x21/PCI6x11 controller does not require any additional components for UltraMedia

support.

3.5.8

SPKROUT and CAUDPWM Usage

The SPKROUT terminal carries the digital audio signal from the PC Card to the system. When a 16-bit PC Card is

configured for I/O mode, the BVD2 terminal becomes the SPKR input terminal from the card. This terminal, in

CardBus applications, is referred to as CAUDIO. SPKR passes a TTL-level binary audio signal to the

PCI6x21/PCI6x11 controller. The CardBus CAUDIO signal also can pass a single-amplitude binary waveform as well

as a PWM signal. The binary audio signal from each PC Card sockets is enabled by bit 1 (SPKROUTEN) of the card

control register (PCI offset 91h, see Section 4.38).

Older controllers support CAUDIO in binary or PWM mode, but use the same output terminal (SPKROUT). Some

audio chips may not support both modes on one terminal and may have a separate terminal for binary and PWM.

The PCI6x21/PCI6x11 implementation includes a signal for PWM, CAUDPWM, which can be routed to an MFUNC

terminal. Bit 2 (AUD2MUX), located in the card control register, is programmed to route a CardBus CAUDIO PWM

terminal to CAUDPWM. See Section 4.36, Multifunction Routing Register, for details on configuring the MFUNC

terminals.

Figure 3−4 illustrates the SPKROUT connection.

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