The PCM1753 and PCM1755 devices have many programmable functions which can be controlled in the software control mode. The functions are controlled by programming the internal registers using the ML, MC, and MD pins.
The serial control interface is a 3-wire serial port, which operates asynchronously to the audio serial interface. The serial control interface is used to program the on-chip mode registers. The control interface includes MD (pin 13), MC (pin 14), and ML (pin 15). The MD pin is the serial data input, used to program the mode registers. The MC pin is the serial bit clock, used to shift data into the control port. The ML pin is the control port latch clock.