ESP32-DevKitC-WROOM

Board Overview

ESP32-DevKitC-WROOM

Name:

esp32_devkitc_wroom

Vendor:

Espressif Systems

Architecture:

xtensa

SoC:

esp32

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Overview

ESP32 is a series of low cost, low power system on a chip microcontrollers with integrated Wi-Fi & dual-mode Bluetooth. The ESP32 series employs a Tensilica Xtensa LX6 microprocessor in both dual-core and single-core variations. ESP32 is created and developed by Espressif Systems, a Shanghai-based Chinese company, and is manufactured by TSMC using their 40nm process. For more information, check ESP32-DevKitC-WROOM [1].

The features include the following:

• Dual core Xtensa microprocessor (LX6), running at 160 or 240MHz

• 520KB of SRAM

• 802.11b/g/n/e/i

• Bluetooth v4.2 BR/EDR and BLE

• Various peripherals:

  • 12-bit ADC with up to 18 channels

  • 2x 8-bit DACs

  • 10x touch sensors

  • Temperature sensor

  • 4x SPI

  • 2x I2S

  • 2x I2C

  • 3x UART

  • SD/SDIO/MMC host

  • Slave (SDIO/SPI)

  • Ethernet MAC

  • CAN bus 2.0

  • IR (RX/TX)

  • Motor PWM

  • LED PWM with up to 16 channels

  • Hall effect sensor

• Cryptographic hardware acceleration (RNG, ECC, RSA, SHA-2, AES)

• 5uA deep sleep current

For more information, check the datasheet at ESP32 Datasheet [2] or the technical reference manual at ESP32 Technical Reference Manual [3].

Asymmetric Multiprocessing (AMP)

ESP32-DevKitC-WROOM allows 2 different applications to be executed in ESP32 SoC. Due to its dual-core architecture, each core can be enabled to execute customized tasks in stand-alone mode and/or exchanging data over OpenAMP framework. See Inter-Processor Communication (IPC) folder as code reference.

Supported Features

The esp32_devkitc_wroom board supports the hardware features listed below.

on-chip / on-board

Feature integrated in the SoC / present on the board.

2 / 2

Number of instances that are enabled / disabled.
Click on the label to see the first instance of this feature in the board/SoC DTS files.

vnd,foo

Compatible string for the Devicetree binding matching the feature.
Click on the link to view the binding documentation.

esp32_devkitc_wroom

/

esp32/appcpuesp32/procpu

esp32_devkitc_wroom/esp32/appcpu target

Type	Location	Description	Compatible
CPU	on-chip	Espressif Xtensa LX6 CPU2	espressif,xtensa-lx6
ADC	on-chip	ESP32 ADC2	espressif,esp32-adc
Bluetooth	on-chip	Bluetooth HCI for Espressif ESP321	espressif,esp32-bt-hci
CAN	on-chip	ESP32 Two-Wire Automotive Interface (TWAI)1	espressif,esp32-twai
Clock control	on-chip	ESP32 RTC (Power & Clock Controller Module) Module1	espressif,esp32-rtc
Counter	on-chip	ESP32 Counter Driver based on RTC Main Timer1	espressif,esp32-rtc-timer
	on-chip	ESP32 general-purpose timers4	espressif,esp32-timer
DAC	on-chip	ESP32 Digital to Analog converter (DAC)1	espressif,esp32-dac
Ethernet	on-chip	ESP32 Ethernet1	espressif,esp32-eth
Flash controller	on-chip	ESP32 flash controller1	espressif,esp32-flash-controller
GPIO & Headers	on-chip	ESP32 GPIO controller2	espressif,esp32-gpio
I2C	on-chip	ESP32 I2C2	espressif,esp32-i2c
Input	on-chip	ESP32 touch sensor input1	espressif,esp32-touch
Interrupt controller	on-chip	ESP32 Interrupt controller1	espressif,esp32-intc
IPM	on-chip	ESP32 soft inter processor message1	espressif,esp32-ipm
Mailbox	on-chip	ESP32 soft mailbox1	espressif,mbox-esp32
MDIO	on-chip	ESP32 MDIO controller1	espressif,esp32-mdio
Memory controller	on-chip	ESP32 pseudo-static RAM controller1	espressif,esp32-psram
MTD	on-chip	Flash node1	soc-nv-flash
	on-chip	Fixed partitions of a flash (or other non-volatile storage) memory1	fixed-partitions
Pin control	on-chip	ESP32 pin controller1	espressif,esp32-pinctrl
PWM	on-chip	ESP32 LED Control (LEDC)1	espressif,esp32-ledc
	on-chip	ESP32 Motor Control Pulse Width Modulator (MCPWM)2	espressif,esp32-mcpwm
RNG	on-chip	ESP32 TRNG (True Random Number Generator)1	espressif,esp32-trng
SDHC	on-chip	ESP32 SDHC controller1	espressif,esp32-sdhc
	on-chip	ESP32 SDHC controller slot2	espressif,esp32-sdhc-slot
Sensors	on-chip	ESP32 Pulse Counter (PCNT)1	espressif,esp32-pcnt
Serial controller	on-chip	ESP32 UART3	espressif,esp32-uart
SPI	on-chip	ESP32 SPI2	espressif,esp32-spi
SRAM	on-chip	Generic on-chip SRAM description2	mmio-sram
Watchdog	on-chip	ESP32 watchdog1 1	espressif,esp32-watchdog
Wi-Fi	on-chip	ESP32 SoC Wi-Fi1	espressif,esp32-wifi

esp32_devkitc_wroom/esp32/procpu target

Type	Location	Description	Compatible
CPU	on-chip	Espressif Xtensa LX6 CPU2	espressif,xtensa-lx6
ADC	on-chip	ESP32 ADC2	espressif,esp32-adc
Bluetooth	on-chip	Bluetooth HCI for Espressif ESP321	espressif,esp32-bt-hci
CAN	on-chip	ESP32 Two-Wire Automotive Interface (TWAI)1	espressif,esp32-twai
Clock control	on-chip	ESP32 RTC (Power & Clock Controller Module) Module1	espressif,esp32-rtc
Counter	on-chip	ESP32 Counter Driver based on RTC Main Timer1	espressif,esp32-rtc-timer
	on-chip	ESP32 general-purpose timers4	espressif,esp32-timer
DAC	on-chip	ESP32 Digital to Analog converter (DAC)1	espressif,esp32-dac
Ethernet	on-chip	ESP32 Ethernet1	espressif,esp32-eth
Flash controller	on-chip	ESP32 flash controller1	espressif,esp32-flash-controller
GPIO & Headers	on-chip	ESP32 GPIO controller2	espressif,esp32-gpio
I2C	on-chip	ESP32 I2C1 1	espressif,esp32-i2c
Input	on-chip	ESP32 touch sensor input1	espressif,esp32-touch
	on-board	Group of GPIO-bound input keys1	gpio-keys
Interrupt controller	on-chip	ESP32 Interrupt controller1	espressif,esp32-intc
IPM	on-chip	ESP32 soft inter processor message1	espressif,esp32-ipm
Mailbox	on-chip	ESP32 soft mailbox1	espressif,mbox-esp32
MDIO	on-chip	ESP32 MDIO controller1	espressif,esp32-mdio
Memory controller	on-chip	ESP32 pseudo-static RAM controller1	espressif,esp32-psram
MTD	on-chip	Flash node1	soc-nv-flash
	on-chip	Fixed partitions of a flash (or other non-volatile storage) memory1	fixed-partitions
Pin control	on-chip	ESP32 pin controller1	espressif,esp32-pinctrl
PWM	on-chip	ESP32 LED Control (LEDC)1	espressif,esp32-ledc
	on-chip	ESP32 Motor Control Pulse Width Modulator (MCPWM)2	espressif,esp32-mcpwm
RNG	on-chip	ESP32 TRNG (True Random Number Generator)1	espressif,esp32-trng
SDHC	on-chip	ESP32 SDHC controller1	espressif,esp32-sdhc
	on-chip	ESP32 SDHC controller slot2	espressif,esp32-sdhc-slot
Sensors	on-chip	ESP32 Pulse Counter (PCNT)1	espressif,esp32-pcnt
Serial controller	on-chip	ESP32 UART1 2	espressif,esp32-uart
SPI	on-chip	ESP32 SPI2	espressif,esp32-spi
SRAM	on-chip	Generic on-chip SRAM description2	mmio-sram
Watchdog	on-chip	ESP32 watchdog1 1	espressif,esp32-watchdog
Wi-Fi	on-chip	ESP32 SoC Wi-Fi1	espressif,esp32-wifi

System requirements

Prerequisites

Espressif HAL requires WiFi and Bluetooth binary blobs in order work. Run the command below to retrieve those files.

west blobs fetch hal_espressif

Note

It is recommended running the command above after west update.

Building & Flashing

Simple boot

The board could be loaded using the single binary image, without 2nd stage bootloader. It is the default option when building the application without additional configuration.

Note

Simple boot does not provide any security features nor OTA updates.

MCUboot bootloader

User may choose to use MCUboot bootloader instead. In that case the bootloader must be built (and flashed) at least once.

There are two options to be used when building an application:

1. Sysbuild

2. Manual build

Note

User can select the MCUboot bootloader by adding the following line to the board default configuration file.

CONFIG_BOOTLOADER_MCUBOOT=y

Sysbuild

The sysbuild makes possible to build and flash all necessary images needed to bootstrap the board with the ESP32 SoC.

To build the sample application using sysbuild use the command:

west build -b esp_wrover_kit --sysbuild samples/hello_world

By default, the ESP32 sysbuild creates bootloader (MCUboot) and application images. But it can be configured to create other kind of images.

Build directory structure created by sysbuild is different from traditional Zephyr build. Output is structured by the domain subdirectories:

build/
├── hello_world
│   └── zephyr
│       ├── zephyr.elf
│       └── zephyr.bin
├── mcuboot
│    └── zephyr
│       ├── zephyr.elf
│       └── zephyr.bin
└── domains.yaml

Note

With --sysbuild option the bootloader will be re-build and re-flash every time the pristine build is used.

For more information about the system build please read the Sysbuild (System build) documentation.

Manual build

During the development cycle, it is intended to build & flash as quickly possible. For that reason, images can be built one at a time using traditional build.

The instructions following are relevant for both manual build and sysbuild. The only difference is the structure of the build directory.

Note

Remember that bootloader (MCUboot) needs to be flash at least once.

Build and flash applications as usual (see Building an Application and Run an Application for more details).

# From the root of the zephyr repository
west build -b esp32_devkitc_wroom/esp32/procpu samples/hello_world

The usual flash target will work with the esp32_devkitc_wroom board configuration. Here is an example for the Hello World application.

# From the root of the zephyr repository
west build -b esp32_devkitc_wroom/esp32/procpu samples/hello_world
west flash

Open the serial monitor using the following command:

west espressif monitor

After the board has automatically reset and booted, you should see the following message in the monitor:

***** Booting Zephyr OS vx.x.x-xxx-gxxxxxxxxxxxx *****
Hello World! esp32_devkitc_wroom

Debugging

ESP32 support on OpenOCD is available at OpenOCD ESP32 [5].

On the ESP32-DevKitC-WROOM board, the JTAG pins are not run to a standard connector (e.g. ARM 20-pin) and need to be manually connected to the external programmer (e.g. a Flyswatter2):

ESP32 pin	JTAG pin
3V3	VTRef
EN	nTRST
IO14	TMS
IO12	TDI
GND	GND
IO13	TCK
IO15	TDO

Further documentation can be obtained from the SoC vendor in JTAG debugging for ESP32 [4].

Here is an example for building the Hello World application.

# From the root of the zephyr repository
west build -b esp32_devkitc_wroom/esp32/procpu samples/hello_world
west flash

You can debug an application in the usual way. Here is an example for the Hello World application.

# From the root of the zephyr repository
west build -b esp32_devkitc_wroom/esp32/procpu samples/hello_world
west debug

Note on Debugging with GDB Stub

GDB stub is enabled on ESP32.

• When adding breakpoints, please use hardware breakpoints with command hbreak. Command break uses software breakpoints which requires modifying memory content to insert break/trap instructions. This does not work as the code is on flash which cannot be randomly accessed for modification.

References

[1]

https://docs.espressif.com/projects/esp-idf/en/stable/esp32/hw-reference/esp32/get-started-devkitc.html#

[2]

https://www.espressif.com/sites/default/files/documentation/esp32_datasheet_en.pdf

[3]

https://espressif.com/sites/default/files/documentation/esp32_technical_reference_manual_en.pdf

[4]

https://docs.espressif.com/projects/esp-idf/en/latest/esp32/api-guides/jtag-debugging/index.html

[5]

https://github.com/espressif/openocd-esp32/releases