STMicroelectronics Empowers Type-C Power Delivery with STM32 Microcontrollers

STMicroelectronics has added a USB Type-C connector system interface (UCSI) library in the STM32Cube software ecosystem for STM32 microcontrollers (MCUs) to accelerate development of USB-C Power Delivery (PD) applications.

The X-CUBE-UCSI is a turnkey UCSI-certified solution with ready-to-use hardware and firmware examples to implement standardized communication using an STM32 MCU as a UCSI PD controller. These are designs that a customer can simply copy and paste, which have been optimized for its bill-of-materials (BoM).

The software lets the MCU connect to the main system processor and exchange information with the operating system using the UCSI protocol, while controlling the USB-C attachment and PD protocol. The main processor, which can be a System-on-Chip (SoC), application processor, or STM32MP microprocessor, acts as the UCSI operating system policy manager (OPM). The PD controller on-board the STM32 microcontrollers performs as UCSI platform policy manager (PPM). The necessary USB type-C and Power delivery (UCPD) peripheral is available in various STM32 MCUs. The lowest-cost variant is the STM32G0 line, making an ideal low-pin-count companion chip for the MPU dedicated to handling the PD functionality.

The software also allows STM32 MCU firmware programming via the main processor, in the production line as well as during the lifetime of the application. The main processor uses the UCSI driver, from Microsoft or available in the Linux community, and associated commands to exchange data with the PD controller. In addition to saving development time, this extends interoperability between USB-C devices to support the latest use cases the technology offers.

X-CUBE-UCSI STM32Cube expansion software helps developers to build a USB PD dual-role power (DRP) application as well as to support alternate-mode commands.

Enabling a quick start to development, the USB-certified (TID 8088) Discovery board, STM32MP135F-DK, contains an STM32MP135 as the main application processor, connected to an STM32G071 MCU as the UCSI PD controller. The board also features ST’s TCPP03-M20 USB Type-C high-voltage port-protection IC.

More than 500 standard STM32 MCUs are now available with ST’s UCPD Power Delivery controller peripheral implemented on-chip. Moreover, the rich analog and digital features of STM32 MCUs provide extra flexibility as a port expander to implement additional functions not supported by the main processor.