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4. Peripherals and Sensors

4.1.10 Universal Asynchronous Receiver Transmitter (UART)

ESP32 has three UART interfaces, i.e., UART0, UART1 and UART2, which provide asynchronous communication

(RS232 and RS485) and IrDA support, communicating at a speed of up to 5 Mbps. UART provides hardware

management of the CTS and RTS signals and software flow control (XON and XOFF). All of the interfaces can be

accessed by the DMA controller or directly by the CPU.

4.1.11 I²C Interface

ESP32 has two I²C bus interfaces which can serve as I²C master or slave, depending on the user’s configuration.

The I²C interfaces support:

• Standard mode (100 Kbit/s)

• Fast mode (400 Kbit/s)

• Up to 5 MHz, yet constrained by SDA pull-up strength

• 7-bit/10-bit addressing mode

• Dual addressing mode

Users can program command registers to control I²C interfaces, so that they have more flexibility.

4.1.12 I²S Interface

Two standard I²S interfaces are available in ESP32. They can be operated in master or slave mode, in full duplex

and half-duplex communication modes, and can be configured to operate with an 8-/16-/32-/48-/64-bit resolution

as input or output channels. BCK clock frequency, from 10 kHz up to 40 MHz, is supported. When one or

both of the I²S interfaces are configured in the master mode, the master clock can be output to the external

DAC/CODEC.

Both of the I²S interfaces have dedicated DMA controllers. PDM and BT PCM interfaces are supported.

4.1.13 Infrared Remote Controller

The infrared remote controller supports eight channels of infrared remote transmission and receiving. By program-

ming the pulse waveform, it supports various infrared protocols. Eight channels share a 512 x 32-bit block of

memory to store the transmitting or receiving waveform.

4.1.14 Pulse Counter

The pulse counter captures pulse and counts pulse edges through seven modes. It has eight channels, each of

which captures four signals at a time. The four input signals include two pulse signals and two control signals.

When the counter reaches a defined threshold, an interrupt is generated.

4.1.15 Pulse Width Modulation (PWM)

The Pulse Width Modulation (PWM) controller can be used for driving digital motors and smart lights. The controller

consists of PWM timers, the PWM operator and a dedicated capture sub-module. Each timer provides timing in

synchronous or independent form, and each PWM operator generates a waveform for one PWM channel. The

dedicated capture sub-module can accurately capture events with external timing.

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ESP32 Datasheet V3.0

ESP32 Datasheet(PDF) 33 Page - ESPRESSIF SYSTEMS (SHANGHAI) CO., LTD.