November 2010
Doc ID 15846 Rev 1
1/31
UM0718
User manual
User manual for the USB to PMBus bridge
demonstration board
Introduction
The power management bus (PMBus) is a variant of the system management bus (SMBus)
which is targeted at digital management of power supplies. Like the SMBus, it is a relatively
slow speed two-wire communications protocol based on I
2
C. The PMBus protocol helps to
establish the first truly open communications standard for the digital control of power
systems facilitating the programming, control, and real-time monitoring of compliant power
conversion products.
This document describes how to set up and use the USB to PMBus bridge board for PMBus
communication. The objective of this demonstration board is to show the features and
capabilities of the PMBus using the ST7 I
2
C peripheral, to support the standard PMBus
commands. This demonstration board has an ST72651AR6 microcontroller (MCU) which
has an I
2
C peripheral. This microcontroller acts as the PMBus master. The demonstration
board works with a PC GUI and controls one or more PMBus compatible slaves connected
on the shared bus. The main purpose of this board is to interface with any compatible
PMBus devices making use of the supported set of commands.
The firmware of this application performs the PMBus bus protocols mentioned in PMBus
power system management protocol specification v1.1. The firmware is in C language.
shows the block diagram of this demonstration board.
Figure 1.
USB to PMBus bridge - block diagram
www.BDTIC.com/ST
