非常好的三角波的发生器，可以设置频率等参数-Very nice triangular wave generator, can set the frequency parameter

三角波生成程序，用于生成初始信号对系统进行模拟。-Triangle-wave generation process, used to generate the initial signal of the system simulation.

在dac 上显示一个波图，刚刚输出的时候是sine 的图 开动按钮后发出不同的图像-Write a C program that creates a waveform generator. It should start by outputting a sine wave to DAC0. Each time SW1 is pressed then released, the wave form should change, first to a triangle wave, then