LS7166

The LS7166 is a versatile 24-bit quadrature decoder/counter chip from LSI Corporation. It is designed to interface directly with motor encoders, decoding and counting pulses from the encoder's A and B channels. This allows microcontrollers to read the current count value without requiring additional timers, simplifying motor encoder integration.

The LS7166 features an 8-bit bi-directional data bus for communication with a microcontroller, along with several control lines. It supports multiple counting modes, including binary, BCD, and time units (hours/minutes/seconds), with binary counting being essential for motor-related applications. A notable feature is the divide-by-n mode, which allows setting a fixed value for the count register upon rollover. This is particularly useful for motor applications, enabling the determination of the motor's exact position by setting the fixed value to the number of pulses per full rotation.

While the provided information focuses on divide-by-n binary quadrature mode, the chip offers more advanced features detailed in its datasheet. The LS7166 can also function as an up/down counter for applications beyond motor encoding. A similar chip, the LS7366R, is available and utilizes an SPI bus for communication instead of a parallel interface.