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Software Control (PCM1772)
Register Write Operation (PCM1772)
MSB
0 IDX6 IDX5 IDX4 IDX3 IDX2 IDX1 IDX0 D7 D6 D5 D4 D3 D2 D1 D000
LSB
Register Index (or Address) Register Data
R0001-01
MC
MS
MD
16 Bits
(1) Single Write Operation
MSB LSB MSB
(2) Continuous Write Operation
MSB LSB MSB LSB MSB LSB
16 Bits x N Frames
MC
MS
MD
N Frames
T0012-01
PCM1772 , PCM1773
SLES010G – SEPTEMBER 2001 – REVISED MARCH 2007
The PCM1772 device has many programmable functions that can be controlled in the software control mode.
The functions are controlled by programming the internal registers using MS, MC, and MD.
The software control interface is a 3-wire serial port that operates asynchronously to the serial audio interface.
The serial control interface is used to program the on-chip mode registers. MD is the serial data input, used to
program the mode registers. MC is the serial bit clock, used to shift data into the control port. MS is the mode
control port select signal.
All write operations for the serial control port use 16-bit data words. Figure 25 shows the control data word
format. The most significant bit must be 0. Seven bits, labeled IDX[6:0], set the register index (or address) for
the write operation. The eight least significant bits, D[7:0], contain the data to be written to the register specified
by IDX[6:0].
Figure 26 shows the functional timing diagram for writing to the serial control port. To write data into the mode
register, data is clocked into an internal shift register on the rising edge of the MC clock. Serial data can change
on the falling edge of the MC clock and must be stable on the rising edge of the MC clock. The MS signal must
be low during the write mode, and the rising edge of the MS signal must be aligned with the falling edge of the
last MC clock pulse in the 16-bit frame. The MC clock can run continuously between transactions while the MS
signal is low.
Figure 25. Control Data Word Format for MD
Figure 26. Register Write Operation
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