Abstract

The trend in wearable devices is toward low-power, ultra-small form factors, and the integration of diverse functions into a single application smartwatch. Smartwatches are the most widely known application, but the reach of smartwatches is expanding to include rings, bands, earphones, and more. Wearable designs often incorporate a variety of communication protocols, including Bluetooth®, LTE, 5G, SPI, and I2C, within a small device area. Consequently, signal interference can occur at any time within the application, and effectively managing this interference is a crucial skill and expertise. This application report demonstrates communication issues (particularly SPI) that can arise in increasingly smaller and more complex wearable designs, and how to identify and resolve causes.