Solution
SSI (Serial Synchronous Interface) is a widely used serial interface between an absolute position sensor and a controller. SSI uses a clock pulse train from a controller to initiate a gated output from the sensor.
Position data is continually updated by the sensor and made available to the shift register. Between each clock pulse train there is a minimum dwell of 25 microseconds during which fresh data is moved into the register. Data is shifted out when the sensor receives a pulse train from the controller. When the least significant bit (LSB) goes HIGH and the minimum dwell time has elapsed, new data is available to read. Refer to the diagrams below for examples of a typical SSI block diagram, timing diagram, and a timing diagram showing the 25 microsecond dwell between data sets.
SSI Block Diagram
SSI Timing Diagram
SSI Timing for Sequential Measurements