I Introduction
Embedded microprocessors are divided into 3 categories: 8-bit, 16-bit and 32-bit microprocessor, depending on the demand of performance, cost, power, and programbility. For simple control system witch requires extremely low cost and low power, 8-bit microprocessor is the best choice [2]. But it often has low programbility that the software designers have to write the program in assembly language. In contrast to 8-bit microprocessor, 32-bit microprocessor, for example, ARM have high programbility, high performance and are widely used for applications need high computation such as cellular phone and PDA [3]. As for 16-bit microprocessor, they have higher performance power than 8-bit microprocessors [4] and lower power consumption than 32-bit microprocessors, are often used in 16-bit applications such as disk driver controller, airbags and cellular communication [4].