Each table has 16 items, in which channel selection, resolution and attenuation are stored. The pattern table that defines the conversion rules for each SAR ADC. Range: 0 ~ 16 (0: Don’t change the pattern table setting). Pattern table length for digital controller. Set the upper limit of the number of ADC conversion triggers. If the number of ADC conversion trigger count is equal to the limit_num, the conversion is stopped. ReturnĮnable the function of limiting ADC conversion times. ADC1 should be configured for 12 bit readings, as the hall sensor readings are low values and do not cover the full range of the ADC. The ADC1 module must be enabled by calling adc1_config_width() before calling hall_sensor_read(). Do not configure these channels for use as ADC channels.

The Hall Sensor uses channels 0 and 3 of ADC1. Please refer to section 3.11 of ‘ECO_and_Workarounds_for_Bugs_in_ESP32’ for the description of this issue. When enabling power for any of these peripherals, ignore input from GPIO36 and GPIO39. When the power switch of SARADC1, SARADC2, HALL sensor and AMP sensor is turned on, the input of GPIO36 and GPIO39 will be pulled down for about 80ns. Src: I2S DMA data source, I2S DMA can get data from digital signals or from ADC.Įsp_err_t adc_i2s_mode_init ( adc_unit_t adc_unit, adc_channel_t channel ) ¶ It comes handy to calibrate ADC reading and this is discussed in section Minimizing Noise.įunctions ¶ esp_err_t adc_set_i2s_data_source ( adc_i2s_source_t src ) ¶ There is another specific function adc_vref_to_gpio() used to route internal reference voltage to a GPIO pin. To do so, call function adc1_ulp_enable() and then set precision and attenuation as discussed above. This API provides convenient way to configure ADC1 for reading from ULP. Otherwise it may affect the measurement of low value signal from the sensor. Do not connect anything else to these pins and do not change their configuration.

Note that even the hall sensor is internal to ESP32, reading from it uses channels 0 and 3 of ADC1 (GPIO 36 and 39). It is also possible to read the internal hall effect sensor via ADC1 by calling dedicated function hall_sensor_read(). Use the return code to see whether the reading is successful.

Since the ADC2 is shared with the WIFI module, which has higher priority, reading operation of adc2_get_raw() will fail between esp_wifi_start() and esp_wifi_stop().

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