Generic ESP32-WROOM-32 boards

Support for generic ESP32-WROOM-32 boards. More...

Detailed Description

Support for generic ESP32-WROOM-32 boards.

Gunar Schorcht

Table of Contents

  1. Overview
  2. Hardware
    1. MCU
    2. Board Configuration
    3. Board Pinout
    4. Optional Hardware Configurations
  3. Flashing the Device

Overview    [TOC]

This board definition covers not just a single board, but rather a large set of generic boards that use an ESP32-WROOM-32 module and simply break out all GPIOs to external pads without having any special hardware or interfaces on-board. Examples are Espressif's ESP32-DevKitC or NodeMCU-ESP32S and a large number of clones.

Espressif ESP32-DevKitC V4

Hardware    [TOC]

This section describes

MCU    [TOC]

Most features of the board are provided by the ESP32 SoC. For detailed information about the ESP32, see section MCU ESP32.

Board Configuration    [TOC]

Generic ESP32-WROOM-32 boards do not have special hardware on board and all GPIOs are simply broken out for flexibility. Therefore, the board configuration is the most flexible one with provides:

18 x ADC channels at maximum 2 x DAC channels at maximum 2 x SPI at maximum 1 x I2C at maximum 2 x UART

Since all GPIOs have broken out, GPIOs can be used for different purposes in different applications. For flexibility, GPIOs can be listed in various peripheral configurations. For example, GPIO13 is used in the ADC channel definition and the definition of the MOSI signal of SPI_DEV(0).

This is possible because GPIOs are only used for a specific peripheral interface when

That is, the purpose for which a GPIO is used depends on which module or function is used first.

For example, if module periph_i2c is not used, the GPIOs listed in I2C configuration can be used for the other purposes.

The following table shows the default board configuration, which is sorted according to the defined functionality of GPIOs. This configuration can be overridden by application-specific configurations.

Function GPIOs Remarks Configuration
see ADC Channels
DAC GPIO25, GPIO26 refer
PWM_DEV(0) GPIO0, GPIO2, GPIO4, GPIO16, GPIO17 - DAC Channels
PWM_DEV(1) GPIO27, GPIO32, GPIO33 - PWM Channels
I2C_DEV(0):SDA GPIO21 I2C Interfaces
I2C_DEV(0):SCL GPIO22 I2C Interfaces
SPI_DEV(0):CLK GPIO18 VSPI is used SPI Interfaces
SPI_DEV(0):MISO GPIO19 VSPI is used SPI Interfaces
SPI_DEV(0):MOSI GPIO23 VSPI is used SPI Interfaces
SPI_DEV(0):CS0 GPIO5 VSPI is used SPI Interfaces
SPI_DEV(1):CLK GPIO14 HSPI is used SPI Interfaces
SPI_DEV(1):MISO GPIO12 HSPI is used SPI Interfaces
SPI_DEV(1):MOSI GPIO13 HSPI is used SPI Interfaces
SPI_DEV(1):CS0 GPIO15 HSPI is used SPI Interfaces
UART_DEV(0):TxD GPIO1 Console (configuration is fixed) UART interfaces
UART_DEV(0):RxD GPIO3 Console (configuration is fixed) UART interfaces
UART_DEV(1):TxD GPIO10 not available in qout and qio flash mode UART interfaces
UART_DEV(1):RxD GPIO9 not available in qout and qio flash mode UART interfaces
  • The configuration of ADC channels contains all ESP32 GPIOs that can be used as ADC channels.
  • The configuration of DAC channels contains all ESP32 GPIOs that can be used as DAC channels.
  • GPIO9 and GIOP10 can only be used in dout and dio flash modes.

For detailed information about the configuration of ESP32 boards, see section Common Peripherals.

Optional Hardware Configurations    [TOC]

MRF24J40-based IEEE 802.15.4 radio modules and ENC28J60-based Ethernet network interface modules have been tested with the board. You could use the following code in your application-specific configuration to use such modules:

#ifdef BOARD_ESP32_WROOM-32
#define MRF24J40_PARAM_CS GPIO16 /* MRF24J40 CS signal */
#define MRF24J40_PARAM_RESET GPIO17 /* MRF24J40 RESET signal */
#define MRF24J40_PARAM_INT GPIO34 /* MRF24J40 INT signal */
#define MRF24J40_PARAM_SPI_CLK SPI_CLK_1MHZ /* SPI clock frequency */
#define ENC28J80_PARAM_CS GPIO32 /* ENC28J80 CS signal */
#define ENC28J80_PARAM_RESET GPIO33 /* ENC28J80 RESET signal */
#define ENC28J80_PARAM_INT GPIO35 /* ENC28J80 INT signal */

For other parameters, the default values defined by the drivers can be used.

The RESET signal of MRF24J40 and ENC28J60 based modules can also be connected to the RST pin of the board (see pinout) to keep the configured GPIO free for other purposes.

Board Pinout    [TOC]

The following figure shows the pinout of the defined default configuration for the EPS32-DevKitC board as an example of generic ESP32-WROOM-32 boards. The light green GPIOs are not used by configured on-board hardware components and can be used for any purpose. However, if optional off-board hardware modules are used, these GPIOs may also be occupied, see optional functions in table board configuration.

The corresponding board schematics can be found her here

EPS32-DevKitC V4 Pinout

Flashing the Device    [TOC]

Flashing RIOT is quite easy. The board has a Micro-USB connector with reset/boot/flash logic. Just connect the board to your host computer and type using the programming port:

make flash BOARD=esp32-wroom-32 ...

For detailed information about ESP32 as well as configuring and compiling RIOT for ESP32 boards, see RIOT-OS on ESP32 boards.


file  arduino_board.h
 Board specific configuration for the Arduino API.
file  arduino_pinmap.h
 Mapping from MCU pins to Arduino pins.
file  board.h
 Board specific definitions for generic ESP32-WROOM-32 boards.
file  gpio_params.h
 Board specific configuration of direct mapped GPIOs.
file  periph_conf.h
 Peripheral MCU configuration for generic ESP32-WROOM-32 boards.