[Olimex ESP32-EVB](https://github.com/OLIMEX/ESP32-EVB) and [Olimex ESP32-GATEWAY](https://github.com/OLIMEX/ESP32-GATEWAY) are open source hardware boards which use the ESP32-WROOM module. The key features of the boards are:
- Ethernet LAN interface
- MicroSD card interface
- IR interface (Olimex ESP32-EVB only)
- CAN interface (Olimex ESP32-EVB only)
- two Relais (Olimex ESP32-EVB only)
- [UEXT](https://www.olimex.com/Products/Modules/UEXT/) connector with I2C, SPI and UART interfaces (Olimex ESP32-EVB only)
Using the UEXT connector, a lot of [off-board hardware modules](https://www.olimex.com/Products/Modules/) can be connected to Olimex ESP32-EVB to extend the hardware without the need for soldering iron or breadboards.
Because of the differences in the on-board hardware, it is necessary to add the following line to the makefile of the application to use the according configuration for Olimex ESP32-GATEWAY:
```
USEMODULE += olimex_esp32_gateway
```
@image html "https://gitlab.com/gschorcht/RIOT.wiki-Images/raw/master/esp32/Olimex_ESP32-EVB_GATEWAY.png?inline=false" "Olimex ESP32-EVB (left) and Olimex ESP32-GATEWAY (right)"
Most features of the boards are provided by the ESP32 SoC. The following table summarizes these features and gives an overview of which of these features are supported by RIOT. For detailed information about the ESP32, see section \ref esp32_mcu "MCU ESP32".
<center>
MCU | ESP32 | Supported by RIOT
------------|-----------|------------------
Vendor | Espressif | |
Cores | 1 or 2 x Tensilica Xtensa LX6 | 1 core
FPU | yes (ULP - Ultra low power co-processor) | no
Olimex ESP32-EVB and Olimex ESP32-GATEWAY have the following on-board components:
- Ethernet LAN interface
- MicroSD card interface
- IR interface (Olimex ESP32-EVB only)
- CAN interface (Olimex ESP32-EVB only)
- two Relais (Olimex ESP32-EVB only)
- [UEXT](https://www.olimex.com/Products/Modules/UEXT/) connector with I2C, SPI and UART interfaces (Olimex ESP32-EVB only)
The following table shows the default board configuration, which is sorted according to the defined functionality of GPIOs. This configuration can be overridden by \ref esp32_app_spec_conf "application-specific configurations".
- To use the board configuration for Olimex-ESP32-GATEWAY, it is necessary to add the following line to makefile of the application:<br><br>
```
USEMODULE += olimex_esp32_gateway
```
- GPIO9 and GIOP10 can only be used in **dout** and **dio** \ref esp32_flash_modes "flash modes".
- It might be necessary to remove the SD card or the peripheral hardware attached to the SPI_DEV(0) interface for flashing RIOT. Reason is that the **SPI_DEV(0)** interface uses the HSPI interface with the GPIO2 pin as the MISO signal, which has bootstrapping functionality.
For detailed information about the configuration of ESP32 boards, see section \ref esp32_comm_periph "Common Peripherals".
MRF24J40-based IEEE 802.15.4 radio modules have been tested with the board. You could use the following code in your \ref esp32_app_spec_conf "application-specific configuration" to use such modules:
#define MRF24J40_PARAM_CS GPIO9 /* MRF24J40 CS signal */
#define MRF24J40_PARAM_RESET GPIO10 /* MRF24J40 RESET signal */
#define MRF24J40_PARAM_INT GPIO34 /* MRF24J40 INT signal */
#endif
#endif
```
For other parameters, the default values defined by the drivers can be used.
@note
- Since the Olimex-ESP32-GATEWAY does not break out the GPIO of the HSPI interface SPI_DEV(0), it is not possible to connect such module to Olimex-ESP32-GATEWAY.
- Since the Olimex-ESP32-EVB has a lot of on-board hardware, only a few GPIOs are available for external hardware.
- The **RESET** signal of MRF24J40 based modules can also be connected to the **RST** pin of the board (see \ref esp32_olimex-esp32-evb_pinout "pinout") to keep the configured GPIO free for other purposes.
The following pictures shows the pinout of Olimex ESP32-EVB and Olimex ESP32-GATEWAY boards as defined by the default board configuration. 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 \ref esp32_olimex-esp32-evb_table_board_configuration "optional functions" in table board configuration.
The corresponding board schematics can be found on GitHub for [Olimex ESP32-EVB board](https://github.com/OLIMEX/ESP32-EVB/raw/master/HARDWARE/REV-D/ESP32-EVB_Rev_D.pdf) and for [Olimex ESP32-GATEWAY](https://github.com/OLIMEX/ESP32-GATEWAY/raw/master/HARDWARE/Hardware%20revision%20C/ESP32-GATEWAY_Rev_C.pdf).
\anchor esp32_olimex-esp32-evb_pinout
@image html "https://gitlab.com/gschorcht/RIOT.wiki-Images/raw/master/esp32/Olimex_ESP32-EVB_pinout.png?inline=false" "Olimex ESP32-EVB pinout"
@image html "https://gitlab.com/gschorcht/RIOT.wiki-Images/raw/master/esp32/Olimex_ESP32-GATEWAY_pinout.png?inline=false" "Olimex ESP32-GATEWAY pinout"
## <a name="flashing"> Flashing the Device </a> [[TOC](#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-olimex-evb ...
```
For detailed information about ESP32 as well as configuring and compiling RIOT for ESP32 boards, see \ref esp32_riot.
