The TPS60250 is a high-efficiency， constant-frequency charge pump dc/dc converter

　　that can drive up to five white LEDs for a main display and up to two white LEDs for a

　　subdisplay with regulated constant current for uniform intensity.

　　A microcontroller （MCU） can be used to control the currents for white LEDs via the

　　TPS60250 charge pump through a standard I2C interface， with the MCU acting as the

　　I2C master. This application report describes a simple hardware and software platform

　　to demonstrate a Texas Instruments MSP430 MCU implementing an I2C master

　　interface using two general-purpose I/O pins via I2C software emulation. The MSP430

　　is an ultra low power microcontroller that is ideal for controlling white LEDs in

　　applications such as PDA， PMP， GPS， and cell phone screens.

?