[ESP32] Linux Host for IP-Camera, ESP32 hosted mode

ESP32 is a MCU integrated Wifi solution that basically does not need any host CPU or MCU.

It is very good solution for low speed and small size data transmission, but how about large size data transmission with high perfomance CPU as the host based on  Linux ?

 

Here is Solution from Espressif. 

 

github.com/espressif/esp-hosted

 

ESP-Hosted is a project that support ESP32 slave mode. ESP32 is able to work with high perfomance CPU like Raspberry-Pi or even external ST MCU.

Major features.

1. WiFi can use SPI or SDIO : 802.11b/g/n, Station and Soft AP

2. BT is UART (This is very normal since other BT solution is using UART too.) : BLE, BT BR/EDR

3. Target platform : ESP32, ESP32-S2

4. Tested Host : Raspberry Pi (SDIO, SPI), STM32 (SPI)

Linux 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

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

Throughput test

Over SDIO interface 

 

ESP32 Station mode  : HT20 is faster ? 🤔

Traffic	11n HT20 20Mhz	11n HT40 40Mhz
TCP Tx	30.6 Mbps	24.3 Mbps
TCP Rx	16.0 Mbps	18.8 Mbps
UDP Tx	41.0 Mbps	46.4 Mbps
UDP Rx	27.0 Mbps	26.1 Mbps

SoftAP mode

Traffic	11n HT20 20Mhz	11n 40Mhz
TCP Tx	22.9 Mbps	19.7 Mbps
TCP Rx	17.8 Mbps	16.6 Mbps
UDP Tx	39.5 Mbps	46.3 Mbps
UDP Rx	28.7 Mbps	26.8 Mbps

Hardware connection 

Raspberry-Pi pin	ESP Pin	PinFunction
13	IO13	DAT3
15	IO14	CLK
16	IO15	CMD
18	IO2	DAT0
22	IO4	DAT1
31	EN	ESP Reset
37	IO12	DAT2
39	GND	GND

ESP32 still needs firmware

Pre-released firmware

 

esptool.py -p <serial_port> -b 960000 --before default_reset --after hard_reset write_flash --flash_mode dio --flash_freq 40m --flash_size detect 0x8000 partition-table_sdio_v0.3.bin 0x1000 bootloader_sdio_v0.3.bin 0x10000 esp_hosted_firmware_sdio_v0.3.bin

 

Build step

 

1. you need IDF4.0

2. Here is source code. : github.com/espressif/esp-hosted/tree/master/esp/esp_driver/network_adapter

 

3. idf.py menuconfig

   Select SDIO transport layer 

   Example Configuration -> Transport layer -> SDIO interface -> select

 

4. idf.py -p com11 build flash

 

Host needs Device driver

github.com/espressif/esp-hosted/tree/master/host/linux/host_control

github.com/espressif/esp-hosted/tree/master/host/linux/host_driver/esp32

espressif/esp-hosted