ESP32 DAC

ESP32有兩個DAC通道，通道1鏈接GPIO25, 通道2鏈接GPIO26;

當DAC設置為 “built-in DAC mode”的時候，I2S可以通過DAC發送數據；

使用示例：

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

dac一共有8位，將3.3V電壓按照255均分之后，就是dac的精度的最小單位；

 

API函數如下：

esp_err_tdac_pad_get_io_num(dac_channel_tchannel, gpio_num_t *gpio_num)

獲取指定的DAC通道的GPIO口；

 

esp_err_tdac_output_voltage(dac_channel_tchannel, uint8_t dac_value)

設置DAC的輸出電壓；

 

esp_err_tdac_output_enable(dac_channel_tchannel)

 

DAC的輸出使能；

 

esp_err_tdac_output_disable(dac_channel_tchannel)

 

DAC的輸出失能；

 

esp_err_tdac_i2s_enable()

 

DAC 的I2S使能；

 

esp_err_tdac_i2s_disable()

 

DAC的I2S失能；

 

下面是關於量程的理解：

esp_err_tadc1_config_channel_atten(adc1_channel_tchannel, adc_atten_tatten)

該函數設定制定通道的量程范圍atten;

默認量程是1.1伏特，如果想測量更高的范圍的話，更改atten來更改測量量程，最高測量3.3伏特；

 

Note

在adc1_get_raw()讀值之前，確定atten的函數必須執行完畢；

Note

This function can be called multiple times to configure multiple ADC channels simultaneously. adc1_get_raw() can then be called for any configured channel.

如果想更改量程，這個函數可以多次被調用來更改量程范圍；

 

 

 

When VDD_A is 3.3V:

 

 　　0dB attenuaton (ADC_ATTEN_DB_0) gives full-scale voltage 1.1V

• 2.5dB attenuation (ADC_ATTEN_DB_2_5) gives full-scale voltage 1.5V
• 6dB attenuation (ADC_ATTEN_DB_6) gives full-scale voltage 2.2V
• 11dB attenuation (ADC_ATTEN_DB_11) gives full-scale voltage 3.9V (see note below)

 

 

 

Due to ADC characteristics, most accurate results are obtained within the following approximate voltage ranges:

 

Note

最大電壓對應着最大數值， (depending on ADC1 configured bit width, this value is: 4095 for 12-bits, 2047 for 11-bits, 1023 for 10-bits, 511 for 9 bits.)

Note

At 11dB attenuation the maximum voltage is limited by VDD_A, not the full scale voltage.

 

 　　0dB attenuaton (ADC_ATTEN_DB_0) between 100 and 950mV

• 2.5dB attenuation (ADC_ATTEN_DB_2_5) between 100 and 1250mV
• 6dB attenuation (ADC_ATTEN_DB_6) between 150 to 1750mV
• 11dB attenuation (ADC_ATTEN_DB_11) between 150 to 2450mV

 

 

 

For maximum accuracy, use the ADC calibration APIs and measure voltages within these recommended ranges.

 

 Return

• ESP_OK success
• ESP_ERR_INVALID_ARG Parameter error

Parameters

• channel: ADC1 channel to configure
• atten: Attenuation level