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4. Peripherals and Sensors

4.1.3 Hall Sensor

ESP32 integrates a Hall sensor based on an N-carrier resistor. When the chip is in the magnetic field, the Hall

sensor develops a small voltage laterally on the resistor, which can be directly measured by the ADC.

4.1.4 Digital-to-Analog Converter (DAC)

Two 8-bit DAC channels can be used to convert two digital signals into two analog voltage signal outputs. The

design structure is composed of integrated resistor strings and a buffer. This dual DAC supports power supply as

input voltage reference. The two DAC channels can also support independent conversions.

4.1.5 Touch Sensor

ESP32 has 10 capacitive-sensing GPIOs, which detect variations induced by touching or approaching the GPIOs

with a finger or other objects. The low-noise nature of the design and the high sensitivity of the circuit allow relatively

small pads to be used. Arrays of pads can also be used, so that a larger area or more points can be detected.

The 10 capacitive-sensing GPIOs are listed in Table 9.

Table 9: Capacitive-Sensing GPIOs Available on ESP32

Capacitive-sensing signal name

Pin name

GPIO4

GPIO0

GPIO2

MTDO

MTCK

MTDI

MTMS

GPIO27

32K_XN

32K_XP

4.1.6 Ultra-Low-Power Co-processor

The ULP processor and RTC memory remain powered on during the Deep-sleep mode. Hence, the developer can

store a program for the ULP processor in the RTC slow memory to access the peripheral devices, internal timers

and internal sensors during the Deep-sleep mode. This is useful for designing applications where the CPU needs

to be woken up by an external event, or a timer, or a combination of the two, while maintaining minimal power

consumption.

4.1.7 Ethernet MAC Interface

An IEEE-802.3-2008-compliant Media Access Controller (MAC) is provided for Ethernet LAN communications.

ESP32 requires an external physical interface device (PHY) to connect to the physical LAN bus (twisted-pair, fiber,

etc.). The PHY is connected to ESP32 through 17 signals of MII or nine signals of RMII. The following features are

supported on the Ethernet MAC (EMAC) interface:

• 10 Mbps and 100 Mbps rates

• Dedicated DMA controller allowing high-speed transfer between the dedicated SRAM and Ethernet MAC

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ESP32 Datasheet V3.0

ESP32 Datasheet(PDF) 31 Page - ESPRESSIF SYSTEMS (SHANGHAI) CO., LTD.