dac_continuous_config_t struct

DAC channels' mask for selecting which channels are used.

The number of DMA descriptor, at least 2 descriptors are required The number of descriptors is directly proportional to the max data buffer size while converting in cyclic output but only need to ensure it is greater than '1' in acyclic output Typically, suggest to set the number bigger than 5, in case the DMA stopped while sending a short buffer.

The DMA buffer size, should be within 32~4092 bytes. Each DMA buffer will be attached to a DMA descriptor, i.e. the number of DMA buffer will be equal to the DMA descriptor number The DMA buffer size is not allowed to be greater than 4092 bytes The total DMA buffer size equal to `desc_num * buf_size` Typically, suggest to set the size to the multiple of 4.

The frequency of DAC conversion in continuous mode, unit: Hz The supported range is related to the target and the clock source. For the clock `DAC_DIGI_CLK_SRC_DEFAULT`: the range is 19.6 KHz to several MHz on ESP32 and 77 Hz to several MHz on ESP32-S2. For the clock `DAC_DIGI_CLK_SRC_APLL`: the range is 648 Hz to several MHz on ESP32 and 6 Hz to several MHz on ESP32-S2. Typically not suggest to set the frequency higher than 2 MHz, otherwise the severe distortion will appear.

The offset of the DAC digital data. Range -128~127.

The clock source of digital controller, which can affect the range of supported frequency Currently `DAC_DIGI_CLK_SRC_DEFAULT` and `DAC_DIGI_CLK_SRC_APLL` are available.

The channel mode of continuous mode, only take effect when multiple channels enabled, depends converting the buffer alternately or simultaneously.