基于Cortex-M3 LM3S811的外设驱动程序，包括4*4矩阵键盘驱动，DAC7811驱动，LCD12864串行驱动和LCD12864并行驱动-Based on the Cortex-M3 LM3S811 the peripheral drivers, including the 4* 4 matrix keyboard driver, DAC7811 drive, LCD12864 serial driver and LCD12864 parallel driver

检测dac7811功能,利用循环检测其线性度-Detection of dac7811 function, using the cycle detection the linearity