PCM1606

SLES014B − OCTOBER 2001 − REVISED AUGUST 2002

7

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timing requirements (continued)

audio serial interface

The audio serial interface for the PCM1606 comprises a 5-wire synchronous serial port. It includes LRCK (pin

18), BCK (pin 19), DATA1 (pin 1), DATA2 (pin 2) and DATA3 (pin 3). BCK is the serial audio bit clock and is used

to clock the serial data present on DATA1, DATA2, and DATA3 into the audio interface serial shift registers. Serial

data is clocked into the PCM1606 on the rising edge of BCK. LRCK is the serial audio left/right word clock. LRCK

is used to latch serial data into the serial audio interface internal registers.

Both LRCK and BCK must be synchronous to the system clock. Ideally, it is recommended that LRCK and BCK

be derived from the system clock input or output, SCKI. The left/right clock, LRCK, is operated at the sampling

audio data formats and timing

The data formats are shown in Figure 6. Data formats are selected using the format pins, FMT1 (pin 4) and

FMT0 (pin 5). All formats require binary 2s complement, MSB-first audio data. Figure 3 shows a detailed timing

diagram for the serial audio interface, with the exception of TDM format.

DATA1, DATA2, and DATA3 each carry two audio channels, designated as the left and right channels. The left

channel data always precedes the right channel data in the serial data stream for all data formats. Table 2 shows

the mapping of the digital input data to the analog output pins.

TDM format is able to interface by 3-wire synchronous serial port. All data inputs from DATA1, BCK can be

operated at 128, 256, and 512 times the sampling frequency. The rising edge of LRCK means the start of a data

channel 4, channel 5, and channel 6 data are don’t care.

Figure 4 shows the timing requirements for BCK input for TDM format. Figure 5 shows the detailed timing

diagram for TDM format.

Table 2. Audio Input Data to Analog Output Mapping

DATA INPUT

CHANNEL

ANALOG OUTPUT

DATA1

Left

VOUT1†

DATA1

Right

VOUT2†

DATA2

Left

VOUT3‡

DATA2

Right

VOUT4‡

DATA3

Left

VOUT5‡

DATA3

Right

VOUT6‡

† Up to 192 kHz

‡ Up to 96 kHz