PCM2704,PCM2705

PCM2706,PCM2707

SLES081A − JUNE 2003 – REVISED MAY 2004

www.ti.com

15

DETAILED DESCRIPTION

CLOCK AND RESET

For both USB function and audio function, the PCM2704/5/6/7 requires a 12-MHz (

±500 ppm) clock, which can be

generated by the built-in oscillator using a 12-MHz crystal resonator. The 12-MHz crystal resonator must be

connected to XTI (pin 28 for PCM2704/5, pin 12 for PCM2706/7) and XTO (pin 1 for PCM2704/5, pin 13 for

PCM2706/7) with one large (1-M

Ω) resistor and two small capacitors, the capacitance of which depends on the

specified load capacitance of the crystal resonator. An external clock can be supplied from XTI (pin 28 for

PCM2704/5, pin 12 for PCM2706/7). If an external clock is supplied, XTO (pin 1 for PCM2704/5, pin 13 for

PCM2706/7) must be left open. Because no clock disabling pin is provided, it is not recommended to use the external

clock supply. SSPND (pin 27 for PCM2704/5, pin 11 for PCM2706/7) is unable to use clock disabling.

PCM2704/5, pin 24 for PCM2706/7) exceeding 3 V typical for bus-powered applications. About 700

µs is required

until internal reset release.

OPERATION MODE SELECTION

The PCM2704/5/6/7 has the following mode-select pins.

Power Configuration Select/Host Detection

PSEL (pin 4 for PCM2704/5, pin 16 for PCM2706/7) is dedicated to selecting the power source. This selection affects

determined by HOST (pin 21 for PCM2704/5, pin 3 for PCM2706/7). For self-powered operation, HOST must be

current, the pulldown should be a high-value resistor.)

Table 1. Power Configuration Select

PSEL

DESCRIPTION

0

Self-powered

1

Bus-powered

HOST

DESCRIPTION

0

Detached from USB (self-powered)/100 mA (bus-powered)

1

Attached to USB (self-powered)/500 mA (bus-powered)

Function Select (PCM2706/7)

interface is required, FSEL must be set to LOW. Otherwise, FSEL must be set to HIGH.

Table 2. Function Select

FSEL

DOUT

FUNC0

FUNC1

FUNC2

FUNC3

0

Data out (I2S)

LRCK (I2S)

BCK (I2S)

SYSCK (I2S)

Data in (I2S)

1

S/PDIF data

Next track (HID) (1)

Previous track (HID) (1)

Stop (HID) (1)

Play/pause (HID) (1)

(1) Valid on the PCM2706; no function assigned on the PCM2707.