This application note describes how to use the ST7 I2C peripheral for PMBus communication. It explains the process of using the ST72264G1 microcontroller as the PMBus master to control PMBus compatible slaves, and provides a demonstration board to showcase the PMBus capabilities of ST7.
This document details the implementation of the PMBus protocol using the ST7 I2C peripheral. It explains the firmware architecture required to act as a PMBus master, including initialization sequences and command decoding. The note covers the PMBus protocol description, specifically its relationship with the SMBus standard and extensions like the group command protocol.
The guide provides instructions for a demonstration board built around the ST72F264G1 microcontroller. It outlines system requirements, software setup using PC hyperterminal, and hardware configuration. The document includes examples of normal operation, error conditions such as invalid commands or timeouts, and interfacing results with Artesyn and SiLabs modules.
The peripheral is initialized for a communication speed of 100 KHz.
Both the SMBC and SMBD pins should be pulled up with a 4.7 kΩ resistor.
PMBus devices use seven bit addresses.