ESP-Hosted solution

ESP-Hosted project provides a way to use ESP32 or ESP32-S2 (termed as ESP peripheral) as a communication processor for Wi-Fi and Bluetooth/BLE connectivity. On the host side, ESP-Hosted offers a standard network interface for receiving and transmitting 802.3 frames. On top of the network interface, the host can use its own TCP/IP and TLS stack. For BT connectivity, a standard HCI interface is exposed to the Bluetooth host stack.

Please note that this project doesn't provide a standard 802.11 interface to the host. For the control path between the host and ESP peripheral, ESP-Hosted uses a custom implementation based on Protobuf.

Connectivity Support

ESP hosted solution provides following WLAN and BT/BLE features to host:

• WLAN Features:
  • 802.11b/g/n
  • WLAN Station
  • WLAN Soft AP
• BT/BLE Features:
  • v4.2 BR/EDR and BLE

Supported Hosts

ESP-Hosted solution supports microprocessors running Linux as well as STM32 MCU (STM32F469I). It's possible to port this relatively easily on other MCUs too. We support Raspberry-Pi (3 Model B+, 4 Model B) and STM32 Discovery Board (STM32F469I-DISCO) out of the box.

Supported Transports

ESP-Hosted uses SDIO or SPI interface as a transport interface for data and control path. The host acts as SDIO or SPI host whereas ESP32 or ESP32-S2 acts as a corresponding ESP peripheral. Currently Raspberry Pi supports both SDIO and SPI transport and STM32 supports SPI transport. As a peripheral device, ESP32 supports both SDIO and SPI transport interfaces and ESP32-S2 supports SPI transport interface.

For detailed explanation, please go through -

1. Using Raspberry-Pi as a Linux host
2. Using STM32F469I-DISCO as a MCU host

Feature Matrix

Linux Host

Below table explains which feature is supported on which transport interface for Linux based host.

ESP device	Transport Interface	WLAN support	Virtual serial interface	BT/BLE support
ESP32	SDIO	Yes	Yes	Yes
ESP32	SPI	Yes	Yes	Yes
ESP32	UART	No	No	Yes
ESP32-S2	SDIO	NA	NA	NA
ESP32-S2	SPI	Yes	Yes	NA
ESP32-S2	UART	No	No	NA

MCU Host

Below table explains which feature is supported on which transport interface for MCU based host.

ESP device	Transport Interface	WLAN support	Virtual serial interface	BT/BLE support
ESP32	SDIO	No	No	No
ESP32	SPI	Yes	Yes	HCI interface can be implemented over virtual serial interface
ESP32	UART	No	No	No
ESP32-S2	SDIO	NA	NA	NA
ESP32-S2	SPI	Yes	Yes	NA
ESP32-S2	UART	No	No	NA