说明：  DAC转换驱动程序，DAC为TI公司的10位串行电压型输出的DAC芯片TLC5615,驱动DAC芯片，使其完成000-FFC(TLC5615后两位的值一直为0)输出的转换，LED指示灯对应从暗到亮。
(DAC driver, DAC 10 bit serial voltage output of the DAC chip TLC5615 of TI company, DAC driver chip, the completion of 000-FFC (TLC5615 two bit value has been 0) output conversion, LED corresponding to the indicating lamp from dark to bright.)