设置TAS5715EVM环境变量

　　Introduction

　　Most devices in the TAS57xx audio amplifier series have a 7-bit I 2C address of 0x36 （0011 011）。 These devices can also have an address of 0x34 （0011 010） if the A_SEL pin （or similar pin） is pulled low. The TAS5715 has an address of 0x54 （0101 010） or 0x56 （0101 011）， depending on the polarity of A_SEL （external pulldown for 0x54; external pullup for 0x56， respectively）。 The current graphical user interface （GUI） software for the TAS57xx devices create a Windows environment variable that references only the 0x36 address. Without the correct I 2C address， the PC cannot properly communicate with the TAS5715EVM， so the user must change this environment variable to ensure valid communication. The next section explains how to set the Windows environment variable correctly.