[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)"
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.