nRF70 Series Wi-Fi driver

This driver implements the Wi-Fi® protocol for the nRF70 FullMAC Series of devices. FullMAC devices implement the Wi-Fi protocol in the chipset. The driver configures the chipset and transfers the frames to and from the device to the networking stack.

nRF70 Series device is a companion IC and can be used with any Nordic Semiconductor System-on-Chips (SoCs) such as the nRF53 and nRF91 Series SoCs.

You can enable the driver by using the CONFIG_WIFI_NRF700X Kconfig option.

Architecture 

The following figure illustrates the architecture of the nRF70 Series Wi-Fi driver.

nRF70 Series Wi-Fi driver block diagram — nRF70 Series Wi-Fi driver architecture overview

Design overview 

The nRF70 Series Wi-Fi driver follows an OS agnostic design, and the driver implementation is split into OS agnostic and OS (Zephyr) specific code. The OS agnostic code is located in the drivers/wifi/nrf700x/osal/ folder and the OS specific code is located in the drivers/wifi/nrf700x/zephyr/ folder.

The driver supports two modes of operations:

Wi-Fi mode 

In this mode, the driver is designed to be used with the Zephyr networking stack. It is implemented as a network interface driver.

The driver supports the following IEEE 802.11 features:

Wi-Fi 6 (802.11ax) support
WPA3/WPA2 personal security
IEEE 802.11 Power Save modes
Scan only mode
IEEE 802.11 Station (STA) mode

The following features are in the driver code but not yet supported:

IEEE 802.11 AP mode (Soft AP)
Wi-Fi Direct mode

Except for scan only mode, the driver uses host access point daemon (hostapd) to implement AP Media Access Control (MAC) Sublayer Management Entity (AP MLME) and wpa_supplicant to implement 802.1X supplicant.

Radio Test mode 

The nRF70 Series Wi-Fi driver supports Radio Test mode, which you can use to test the RF performance of the nRF70 Series device. This is a build time option that you can enable using the CONFIG_NRF700X_RADIO_TEST Kconfig option.

For more details about using this driver in Radio Test mode, see Wi-Fi: Radio test.

Driver to nRF70 Series device communication 

The driver communicates with the nRF70 Series device using the QSPI/SPI interface. The driver uses the QSPI/SPI interface to send commands to the nRF70 Series device, and to transfer the data to and from the device. The nRF7002 DK uses QSPI whereas the nRF7002 EK uses SPI.

To connect the nRF7002 EK to the SoC, the nrf7002ek shield is required.

Configuration 

The nRF70 Series Wi-Fi driver has the following configuration options:

Kconfig configuration 

CONFIG_WIFI_NRF700X

(bool) nRF700x driver

Nordic Wi-Fi Driver

CONFIG_WIFI_NRF700X_BUS_LOG_LEVEL

(unknown)

None

CONFIG_NRF700X_SCAN_ONLY_MODE

(bool)

None

CONFIG_NRF700X_STA_MODE

(bool) Enable nRF700X STA mode

None

CONFIG_NRF_WIFI_IF_AUTO_START

(bool) Enable Wi-Fi interface auto start on boot

None

CONFIG_NRF_WIFI_PATCHES_EXT_FLASH

(bool) Store nRF700x FW patches in external flash

None

CONFIG_CUSTOM_LINKER_SCRIPT

(string) Custom linker script for nRF700x FW patches

None

CONFIG_NRF_WIFI_LOW_POWER

(bool) Enable low power mode in nRF Wi-Fi chipsets

None

CONFIG_NRF700X_TCP_IP_CHECKSUM_OFFLOAD

(bool) Enable TCP/IP checksum offload

None

CONFIG_NRF700X_REG_DOMAIN

(string) The ISO/IEC alpha2 country code for the country in which this device is currently operating. Default 00 (World regulatory)

None

CONFIG_NET_MGMT_EVENT_STACK_SIZE

(unknown)

None

CONFIG_NRF700X_LOG_VERBOSE

(bool) Maintains the verbosity of information in logs

None

CONFIG_WIFI_NRF700X_LOG_LEVEL

(unknown)

None

CONFIG_NRF700X_ON_QSPI

(bool)

None

CONFIG_NRF700X_ON_SPI

(bool)

None

CONFIG_NRF700X_RADIO_COEX

(bool)

None

CONFIG_NRF700X_WORKQ_STACK_SIZE

(int) Stack size for workqueue

None

CONFIG_NRF700X_WORKQ_MAX_ITEMS

(int) Maximum work items for all workqueues

None

CONFIG_NRF700X_MAX_TX_PENDING_QLEN

(int) Maximum number of pending TX packets

None

CONFIG_NRF700X_RADIO_TEST

(bool) Radio test mode of the nRF700x driver

None

CONFIG_NRF700X_AP_MODE

(bool) Enable Access point mode

None

CONFIG_NRF700X_P2P_MODE

(bool) Enable P2P support in driver

None

CONFIG_NRF700X_DATA_TX

(bool) Enable TX data path in the driver

None

CONFIG_NRF700X_UTIL

(bool) Enable Utility shell in nRF700x driver

None

CONFIG_NRF700X_BT_COEX

(bool) Enable Wi-Fi Bluetooth coexistence support

None

CONFIG_NRF700X_QSPI_LOW_POWER

(bool) Enable low power mode in QSPI

None

CONFIG_NRF700X_ANT_GAIN_2G

(int) Antenna gain for 2.4 GHz band

None

CONFIG_NRF700X_ANT_GAIN_5G_BAND1

(int) Antenna gain for 5 GHz band (5150 MHz - 5350 MHz)

None

CONFIG_NRF700X_ANT_GAIN_5G_BAND2

(int) Antenna gain for 5 GHz band (5470 MHz - 5730 MHz)

None

CONFIG_NRF700X_ANT_GAIN_5G_BAND3

(int) Antenna gain for 5 GHz band (5730 MHz - 5895 MHz)

None

CONFIG_NRF700X_BAND_2G_LOWER_EDGE_BACKOFF

(int) Transmit power backoff (in dB) for lower edge of 2.4 GHz frequency band

None

CONFIG_NRF700X_BAND_2G_UPPER_EDGE_BACKOFF

(int) Transmit power backoff (in dB) for upper edge of 2.4 GHz frequency band

None

CONFIG_NRF700X_BAND_UNII_1_LOWER_EDGE_BACKOFF

(int) Transmit power backoff (in dB) for lower edge of UNII-1 frequency band

None

CONFIG_NRF700X_BAND_UNII_1_UPPER_EDGE_BACKOFF

(int) Transmit power backoff (in dB) for upper edge of UNII-1 frequency band

None

CONFIG_NRF700X_BAND_UNII_2A_LOWER_EDGE_BACKOFF

(int) Transmit power backoff (in dB) for lower edge of UNII-2A frequency band

None

CONFIG_NRF700X_BAND_UNII_2A_UPPER_EDGE_BACKOFF

(int) Transmit power backoff (in dB) for upper edge of UNII-2A frequency band

None

CONFIG_NRF700X_BAND_UNII_2C_LOWER_EDGE_BACKOFF

(int) Transmit power backoff (in dB) for lower edge of UNII-2C frequency band

None

CONFIG_NRF700X_BAND_UNII_2C_UPPER_EDGE_BACKOFF

(int) Transmit power backoff (in dB) for upper edge of UNII-2C frequency band

None

CONFIG_NRF700X_BAND_UNII_3_LOWER_EDGE_BACKOFF

(int) Transmit power backoff (in dB) for lower edge of UNII-3 frequency band

None

CONFIG_NRF700X_BAND_UNII_3_UPPER_EDGE_BACKOFF

(int) Transmit power backoff (in dB) for upper edge of UNII-3 frequency band

None

CONFIG_NRF700X_BAND_UNII_4_LOWER_EDGE_BACKOFF

(int) Transmit power backoff (in dB) for lower edge of UNII-4 frequency band

None

CONFIG_NRF700X_BAND_UNII_4_UPPER_EDGE_BACKOFF

(int) Transmit power backoff (in dB) for upper edge of UNII-4 frequency band

None

CONFIG_NRF700X_RX_NUM_BUFS

(int) Number of RX buffers

None

CONFIG_NRF700X_MAX_TX_AGGREGATION

(int) Maximum number of TX packets to aggregate

None

CONFIG_NRF700X_MAX_TX_TOKENS

(int) Maximum number of TX tokens

None

CONFIG_NRF700X_TX_MAX_DATA_SIZE

(int) Maximum size of TX data

None

CONFIG_NRF700X_RX_MAX_DATA_SIZE

(int) Maximum size of RX data

None

CONFIG_NRF700X_TX_DONE_WQ_ENABLED

(bool) Enable TX done workqueue (impacts performance negatively)

None

CONFIG_NRF700X_RX_WQ_ENABLED

(bool) Enable RX workqueue

None

CONFIG_NUM_METAIRQ_PRIORITIES

(unknown)

None

CONFIG_NRF700X_IRQ_WQ_PRIORITY

(int) Priority of the workqueue for handling IRQs

None

CONFIG_NRF700X_BH_WQ_PRIORITY

(int) Priority of the workqueue for handling bottom half

None

CONFIG_NRF700X_IRQ_WQ_STACK_SIZE

(int) Stack size of the workqueue for handling IRQs

None

CONFIG_NRF700X_BH_WQ_STACK_SIZE

(int) Stack size of the workqueue for handling bottom half

None

CONFIG_NRF700X_TX_DONE_WQ_PRIORITY

(int) Priority of the workqueue for handling TX done

None

CONFIG_NRF700X_TX_DONE_WQ_STACK_SIZE

(int) Stack size of the workqueue for handling TX done

None

CONFIG_NRF700X_RX_WQ_PRIORITY

(int) Priority of the workqueue for handling RX

None

CONFIG_NRF700X_RX_WQ_STACK_SIZE

(int) Stack size of the workqueue for handling RX

None

CONFIG_NRF700X_RPU_PS_IDLE_TIMEOUT_MS

(int) RPU power save idle timeout in milliseconds

None

CONFIG_NRF700X_RPU_EXTEND_TWT_SP

(bool) Enable extending TWT service period

In case frames accepted before beginning of SP are not transmitted before the SP completes then typically they are dropped to conform to SP window as per specification i.e., no transmission outside SP window.

This feature mitigates the frame loss by transmitting even after SP completion by using standard contention mechanism which is allowed in specification but not recommended. As the device is actively transmitting beyond SP, the power consumption increases depending on the amount of traffic available at the start of SP.

Please note that if a frame is sent after SP starts it will be queued and this mechanism is not used.

CONFIG_WIFI_FIXED_MAC_ADDRESS

(string) WiFi Fixed MAC address in format XX:XX:XX:XX:XX:XX

This overrides the MAC address read from OTP. Strictly for testing purposes only.

CONFIG_NRF700X_RSSI_STALE_TIMEOUT_MS

(int) RSSI stale timeout in milliseconds

RSSI stale timeout is the period after which driver queries RPU to get the RSSI the value. If data is active (e.g. ping), driver stores the RSSI value from the received frames and provides this stored information to wpa_supplicant. In this case a higher value will be suitable as stored RSSI value at driver will be updated regularly. If data is not active or after the stale timeout duration, driver queries the RPU to get the RSSI value and provides it to wpa_supplicant. The value should be set to lower value as driver does not store it and requires RPU to provide the info.

CONFIG_HEAP_MEM_POOL_SIZE

(unknown)

None

CONFIG_SYSTEM_WORKQUEUE_STACK_SIZE

(unknown)

None

CONFIG_NET_TX_STACK_SIZE

(unknown)

None

CONFIG_NET_RX_STACK_SIZE

(unknown)

None

CONFIG_NET_TC_TX_COUNT

(unknown)

None

CONFIG_WIFI_MGMT_SCAN_SSID_FILT_MAX

(unknown)

None

CONFIG_NRF_WIFI_BEAMFORMING

(bool) Enable Wi-Fi beamforming. Enabling beamforming can provide slight improvement in performance where as disabling it can provide better power saving in low network activity applications

None

CONFIG_NRF_WIFI_IFACE_MTU

(int) MTU for Wi-Fi interface

None

CONFIG_NRF_WIFI_2G_BAND

(bool) Set operation band to 2.4GHz

None

CONFIG_NRF_WIFI_5G_BAND

(bool) Set operation band to 5GHz

None

CONFIG_NRF_WIFI_OP_BAND

(int) Options to set operation band

Set this option to select frequency band 1 - 2.4GHz 2 - 5GHz 3 - All ( 2.4GHz and 5GHz )

CONFIG_NRF_WIFI_AP_DEAD_DETECT_TIMEOUT

(int) Access point dead detection timeout in seconds

The number of seconds after which AP is declared dead if no beacons are received from the AP. Used to detect AP silently going down e.g., power off.

Devicetree Specification configuration 

The maximum transmit power achieved on a nRF70 Series device-based product depends on the frequency band and operating channel. This varies from chip to chip as well as over different Printed Circuit Board (PCB) designs.

Multiple calibrations and checks are implemented to ensure consistency across channels and devices. However, these values have a dependency on PCB design, which may result in Error Vector Magnitude (EVM) and spectral mask failures. To avoid this problem, you can specify the power ceiling at which the EVM and spectral mask are met for a given PCB design. Additionally, build-time parameters are made available to drivers through the DTS overlay file.

The following code snippet shows an example of the DTS overlay file:

/
{
        nrf70_tx_power_ceiling: nrf70_tx_power_ceiling_node {
                status = "okay";
                compatible = "nordic,nrf700x-tx-power-ceiling";
                max-pwr-2g-dsss = <0x54>;
                max-pwr-2g-mcs0 = <0x40>;
                max-pwr-2g-mcs7 = <0x40>;
                max-pwr-5g-low-mcs0 = <0x38>;
                max-pwr-5g-low-mcs7 = <0x38>;
                max-pwr-5g-mid-mcs0 = <0x38>;
                max-pwr-5g-mid-mcs7 = <0x38>;
                max-pwr-5g-high-mcs0 = <0x38>;
                max-pwr-5g-high-mcs7 = <0x38>;
        };

};

The following table lists the parameters (8-bit unsigned values) defined in the DTS overlay board files:

DTS file parameters
DTS parameter	Description
max-pwr-2g-dsss	Transmit power ceiling for DSSS data rate in 0.25 dBm steps. This is applicable for all DSSS data rates.
max-pwr-2g-mcs0	Transmit power ceiling for MCS0 data rate in 2.4 GHz band in steps of 0.25 dBm steps.
max-pwr-2g-mcs7	Transmit power ceiling for MCS7 data rate in 2.4 GHz band in steps of 0.25 dBm steps.
max-pwr-5g-low-mcs0	Transmit power ceiling for MCS0 in lower 5 GHz frequency band in steps of 0.25 dBm. Lower 5 GHz frequency band refers to channels from 36 to 64.
max-pwr-5g-low-mcs7	Transmit power ceiling for MCS7 in lower 5 GHz frequency band in steps of 0.25 dBm.
max-pwr-5g-mid-mcs0	Transmit power ceiling for MCS0 in mid 5 GHz frequency band in steps of 0.25 dBm. Mid 5 GHz frequency band refers to channels from 100 to 132.
max-pwr-5g-mid-mcs7	Transmit power ceiling for MCS7 in mid 5 GHz frequency band in steps of 0.25 dBm.
max-pwr-5g-high-mcs0	Transmit power ceiling for MCS0 in high 5 GHz frequency band in steps of 0.25 dBm. High 5 GHz frequency band refers to channels from 136 to 177.
max-pwr-5g-mid-mcs7	Transmit power ceiling for MCS7 in mid 5 GHz frequency band in steps of 0.25 dBm.

API documentation 

After the nRF70 Series driver has been initialized, the application will see it as an Ethernet interface. To use the Ethernet interface, the application can use Zephyr Network APIs.

Low-level API documentation 

The nRF70 Series Wi-Fi driver provides a low-level API for use cases where the application needs to access the nRF70 Series device directly. This is typically intended for customers who want to use the nRF70 Series device in a different platform than Zephyr.

Modules: