esp32 DAC 余弦波（cosine）输出调试

esp32 有两个 DAC 通道，CH1(GPIO25),  CH2(GPIO26)，这两个通道是固定的，不能重新配置引脚。

测试代码：

    dac_output_enable(DAC_CHANNEL_1);
    dac_output_enable(DAC_CHANNEL_2);
    // dac_output_voltage(DAC_CHANNEL_1, 200);
    

    dac_cw.en_ch = DAC_CHANNEL_1;
    dac_cw.scale = DAC_CW_SCALE_2; //配置振幅
    dac_cw.phase = DAC_CW_PHASE_0; //配置相位
    dac_cw.freq = 55000;  //波形输出频率
    dac_cw.offset = 1;
    esp_err_t result =  dac_cw_generator_config(&dac_cw);
    printf("result = %d\n", result);
    dac_cw_generator_enable();

    dac_output_enable(DAC_CHANNEL_1);
    // dac_output_voltage(DAC_CHANNEL_1, 200);
    

    dac_cw.en_ch = DAC_CHANNEL_2;
    dac_cw.scale = DAC_CW_SCALE_2; //配置振幅
    dac_cw.phase = DAC_CW_PHASE_180; //配置相位
    dac_cw.freq = 55000;  //波形输出频率
    dac_cw.offset = 1;
    result =  dac_cw_generator_config(&dac_cw);
    printf("result = %d\n", result);
    dac_cw_generator_enable();

　　输出的波形：

绿色是CH2 ， 黄色是CH1.