1 Introduction

Multi-motor control is a common design scenario in end applications such as drones and gimbals. For example, a basic 3-axis stabilization system such as drone requires independent and precise control of three BLDC motor drivers to generate the correct motions. In a traditional approach, a single motor driver requires 3 or 6 unique wires for the MCU to apply PWM control signals, and the total wire count in the system scales linearly with the number of motors in the system. This often leads to increased system size and complexity of the design. TI’s proprietary tSPI interface is a powerful protocol designed to reduce the wires required of such multi-motor control applications. Using tSPI-capable devices such as the DRV8311, multiple motors can be controlled by a common set of 4 wires from the MCU with the same physical layout as the ubiquitous SPI interface. The savings can be immense; in the aforementioned 3-axis system, the number of wires required between MCU and motor driver can be reduced from 18 to only 4. This document will provide an overview of tSPI protocol and its applications.