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 a sawtooth wave, then back to a sine wave (repeating forever). Each time

SW2 is pressed and released, the output amplitude should be adjusted by a factor of 2 (full

amplitude, then half amplitude, then quarter amplitude, then back to full amplitude, etc.).

Use the 2.5V internal reference　the ADC12 module. The full amplitude for each wave form

should be　0V to 2.5V, one period should contain 256 samples, and the frequency should

be 15 Hz.

You should use MATLAB to create waveform lookup tables for the sine and triangle waveforms.

For the sawtooth wave, you can either use MATLAB or an internal function to generate the

waveform.