Run Wi-Fi in AP + STA concurrent mode — connect to an upstream AP as a station while simultaneously serving a SoftAP — radio on the coprocessor, application on the host. mcu_host/main/softap_sta.c is a byte-for-byte copy of upstream IDF wifi/softap_sta (WIFI_MODE_APSTA + LWIP NAPT so AP-side clients reach the STA uplink).
| Coprocessor | ESP32 | ESP32-C Series | ESP32-S Series |
|---|---|---|---|
| Support | Yes | Yes | Yes |
| Host Device | ESP32-P4 | ESP32-H2 | Other MCUs | Linux |
|---|---|---|---|---|
| Support | Yes | Yes | Yes | Yes |
| Connection bus | SDIO | SPI Full-Duplex | SPI Half-Duplex | UART |
|---|---|---|---|---|
| Linux host | Yes | Yes | No | No |
| MCU host | Yes | Yes | Yes | Yes |
wifi/apsta/
├── cp/ ESP coprocessor firmware
├── mcu_host/ ESP-IDF MCU host app
└── linux_802_3_host/ Linux host
├── c_app/ native C app
└── kmod/ kernel module
Important
New here? Get a base example working first. Follow Getting Started: Linux or Getting Started: MCU to wire the boards, install tools, choose a transport, and confirm the host↔co-processor handshake. The steps below only add what is specific to this example.
Set up the tools once (from the repo root):
cd /path/to/esp_hosted
./install.sh # install.fish for the fish shell
. ./export.sh # . ./export.fish for the fish shellThe Wi-Fi radio runs on the co-processor firmware — no extra option to enable. Select the transport:
cd examples/wifi/apsta/cp
eh.py set-target esp32c6
eh.py menuconfigComponent config
└── ESP-Hosted
└── Configure coprocessor
└── CP transport
├── Communication bus (co-processor <== bus ==> host)
│ ├── ( ) SPI Full Duplex
│ ├── (X) SDIO <── default
│ ├── ( ) SPI Half Duplex ← MCU host only
│ └── ( ) UART ← MCU host only
└── SDIO Configuration ← clock, GPIOs, checksum (defaults OK)
Each bus has its own settings submenu (pins, clock, checksum) — defaults are fine for bring-up.
Wi-Fi is the default CP feature — no extra dependency config (CONFIG_ESP_HOSTED_CP_FEAT_WIFI=y is already set in cp/sdkconfig.defaults). Then flash and monitor:
eh.py -p <cp_usb_serial_port> flash monitorNote
Base wiring, OS setup, and transport bring-up live in Getting Started: Linux. This section assumes that already works.
Set up the tools once (from the repo root):
cd /path/to/esp_hosted
./install.sh # install.fish for the fish shell
. ./export.sh # . ./export.fish for the fish shellKernel module (creates ethsta0 / ethap0 and /dev/esps0):
cd examples/wifi/apsta/linux_802_3_host/kmod
./build.sh --bus sdio --reload --reset-gpio 518 --clock-mhz 50
# SPI instead: ./build.sh --bus spi --reload --reset-gpio 518 --clock-mhz 10 --spi-mode 3--reload builds, unloads, and reloads with the given module params. On SPI, start at --clock-mhz 10; once stable, raise it in steps to the co-processor's max SPI clock (see Performance).
Native C app — set the SoftAP and upstream STA credentials:
cd examples/wifi/apsta/linux_802_3_host/c_app
eh.py set-target linux
eh.py menuconfigExample Configuration
├── [ ] Use legacy esp_hosted_* compat-surface main
├── (myssid_ap) SoftAP SSID
├── (mypassword) SoftAP Password
├── (1) SoftAP Channel
├── (4) SoftAP max station connections
├── (myssid) Upstream (STA) SSID
└── (mypassword) Upstream (STA) Password
Host dependency config is pre-set in linux_802_3_host/c_app/sdkconfig.defaults (do not remove):
CONFIG_ESP_HOSTED_HOST_FEAT_RPC=y # RPC control path to the CP
CONFIG_ESP_HOSTED_HOST_FEAT_RPC_EXT_V2=y # RPC ext-v2 wire (required)
CONFIG_ESP_HOSTED_HOST_FEAT_WIFI=y # host Wi-Fi feature
CONFIG_ESP_HOSTED_HOST_AUTO_FEAT_INIT=y # auto-init features at boot (Linux host)
CONFIG_ESP_HOSTED_HOST_FEAT_SYSTEM=y # host System feature (FW version / heartbeat / OTA)
CONFIG_ESP_HOSTED_HOST_FEAT_WIFI_AUTO_INIT=y # auto-init Wi-Fi feature
Then build and run:
eh.py build
eh.py run-
On MCU host the IDF example configures LWIP NAPT so AP-side clients reach the internet via the STA uplink.
-
On Linux host, routing between AP and STA netdevs is the kernel's job — the app does not configure NAPT. Set it up out-of-band when needed:
sudo iptables -t nat -A POSTROUTING -o <sta_iface> -j MASQUERADE sudo sysctl -w net.ipv4.ip_forward=1
Substitute
<sta_iface>with the STA-side netdev name (e.g.ethsta0). -
The Linux C app exists in two flavours sharing
main/: native (main.c,eh_host_*) and legacy esp_hosted compat (legacy/main.c), selected byCONFIG_EH_USE_LEGACY_API. -
AP DHCP server is auto-spawned on the host the moment the AP netif starts.
Set up the tools once (from the repo root):
cd /path/to/esp_hosted
./install.sh # install.fish for the fish shell
. ./export.sh # . ./export.fish for the fish shellThe Wi-Fi radio runs on the co-processor firmware — no extra option to enable. Select the transport:
cd examples/wifi/apsta/cp
eh.py set-target esp32c6
eh.py menuconfigComponent config
└── ESP-Hosted
└── Configure coprocessor
└── CP transport
├── Communication bus (co-processor <== bus ==> host)
│ ├── ( ) SPI Full Duplex
│ ├── (X) SDIO <── default
│ ├── ( ) SPI Half Duplex ← MCU host only
│ └── ( ) UART ← MCU host only
└── SDIO Configuration ← clock, GPIOs, checksum (defaults OK)
Each bus has its own settings submenu (pins, clock, checksum) — defaults are fine for bring-up.
Wi-Fi is the default CP feature — no extra dependency config (CONFIG_ESP_HOSTED_CP_FEAT_WIFI=y is already set in cp/sdkconfig.defaults). Then flash and monitor:
eh.py -p <cp_usb_serial_port> flash monitorSet up the tools once (from the repo root):
cd /path/to/esp_hosted
./install.sh # install.fish for the fish shell
. ./export.sh # . ./export.fish for the fish shellSelect the transport (must match the co-processor) and set the SoftAP + STA credentials:
cd examples/wifi/apsta/mcu_host
eh.py set-target esp32p4
eh.py menuconfigComponent config
└── ESP-Hosted
└── Configure host
└── Host transport
├── Communication bus (co-processor <== bus ==> host)
│ ├── ( ) SPI Full Duplex
│ ├── (X) SDIO <── default (match the co-processor)
│ ├── ( ) SPI Half Duplex
│ └── ( ) UART
└── SDIO Configuration ← slot, bus width, GPIOs (defaults OK)
Example Configuration
├── SoftAP Configuration
│ ├── (myssid) WiFi AP SSID
│ ├── (mypassword) WiFi AP Password
│ ├── (1) WiFi AP Channel
│ └── (4) Maximal STA connections
└── STA Configuration
├── (otherapssid) WiFi Remote AP SSID
├── (otherappassword) WiFi Remote AP Password
├── (5) Maximum retry
└── WiFi Scan auth mode threshold
├── ( ) OPEN
├── ( ) WEP
├── ( ) WPA PSK
├── (X) WPA2 PSK <── default
├── ( ) WPA/WPA2 PSK
├── ( ) WPA3 PSK
├── ( ) WPA2/WPA3 PSK
└── ( ) WAPI PSK
Host dependency config is pre-set in mcu_host/sdkconfig.defaults (do not remove):
CONFIG_ESP_HOSTED_HOST_FEAT_RPC=y # RPC control path to the CP
CONFIG_ESP_HOSTED_HOST_FEAT_RPC_EXT_V2=y # RPC ext-v2 wire (required)
CONFIG_ESP_HOSTED_HOST_FEAT_SYSTEM=y # system RPCs
CONFIG_ESP_HOSTED_HOST_FEAT_WIFI=y # host Wi-Fi feature — routes esp_wifi_* to the CP
CONFIG_LWIP_IP_FORWARD=y # forward packets between AP and STA netifs
CONFIG_LWIP_IPV4_NAPT=y # NAPT so SoftAP clients route via the STA uplink
Then flash and monitor:
eh.py -p <host_usb_serial_port> flash monitor- The host boots, receives the co-processor init event, and the capability exchange completes.
- The STA joins the configured upstream AP and gets an IP (watch the host console log).
- The SoftAP starts; a client associates and receives a DHCP lease from the host, which auto-spawns the AP DHCP server when the AP netif comes up.
- The IDF example configures LWIP NAPT, so AP-side clients reach the internet through the STA uplink.