说明：  MSP430F249单片机驱动时间芯片TDC-GP21的程序，采用单片机外围模块SPI通讯，实现时间芯片的初始化，设置，及读取时间。
(MSP430F249 microcontroller chip TDC-GP21 drive time program, the use of single-chip peripheral modules SPI communication, to achieve the chip initialization time, settings, and read the time.)