Datasheet
t
(RST)
Reset Removal
1024 System Clock Periods
RSTB-Pin
Internal Reset
System Clock
t
(RST)
= 40 ns (min)
Reset
T0015-01
RSTB Pulse Duration
SERIAL AUDIO DATA INTERFACE
INTERFACE MODE
DATA FORMAT
PCM1800
SBAS071B – OCTOBER 2000 – REVISED AUGUST 2008 ...............................................................................................................................................
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Figure 21. RSTB-Pin Reset Timing
The PCM1800 interfaces with the audio system through BCK (pin 14), LRCK (pin 13), FSYNC (pin 12), and
DOUT (pin 15).
The PCM1800 supports master and slave modes as interface modes, which are selected by MODE1 (pin 11)
and MODE0 (pin 10), as shown in Table 2 . When in master mode, the PCM1800 provides the timing for serial
audio data communications between the PCM1800 and the digital audio processor or external circuit. When in
slave mode, the PCM1800 receives the timing for data transfer from an external controller.
Table 2. Interface Mode
MODE1 MODE0 INTERFACE MODE
0 0 Slave mode (256/384/512 f
S
)
0 1 Master mode (512 f
S
)
1 0 Master mode (384 f
S
)
1 1 Master mode (256 f
S
)
MASTER MODE
In master mode, BCK, LRCK, and FSYNC are output pins and are controlled by timing generated in the clock
circuitry of the PCM1800.
FSYNC is used to designate the valid data from the PCM1800. The rising edge of FSYNC indicates the starting
point of the converted audio data, and the following edge of this signal indicates the ending point of data. The
frequency of this signal is fixed at 2 × LRCK, and the duty-cycle ratio depends on the data bit length. The
frequency of BCK is fixed at 64 × LRCK.
SLAVE MODE
In slave mode, BCK, LRCK, and FSYNC are input pins. The PCM1800 accepts 64-BCK/LRCK, 48-BCK/LRCK
(only for a 384-f
S
system clock) or 32-BCK/LRCK format (only for 16-bit, right-justified format). FSYNC is used to
enable the BCK signal, and the PCM1800 can shift out the converted data when FSYNC is HIGH.
The PCM1800 supports four audio data formats in both master and slave modes. These data formats are
selected by FMT1 (pin 9) and FMT0 (pin 8), as shown in Table 3 . Figure 22 and Figure 23 illustrate the data
formats in slave mode and master mode, respectively.
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Product Folder Link(s): PCM1800