nRF70 Series devices have a highly configurable coexistence hardware to help mitigate interference between WLAN and Bluetooth® LE/IEEE 802.15.4 devices (Thread®, Zigbee®).

A Packet Traffic Arbitration (PTA) module, connected to the CH logic function, facilitates the mitigation of various interference scenarios through a highly-programmable fabric. The coexistence hardware enables flexible output signals that support interface configurations like 3-wire and 4-wire. The primary schemes supported are:

The following figure shows the architecture of the coexistence hardware with details about the PTA control lines.

Figure 1. Coexistence hardware architecture
Coexistence hardware architecture
Table 1. Coexistence hardware signals
Signal name I/O Requirement Bluetooth LE/IEEE 802.15.4 signal (3-wire/4-wire) Description Scan-only function
COEX_REQ Input Mandatory for 3-wire and 4-wire SR_REQUEST Bluetooth LE/IEEE 802.15.4 device requesting a TX/RX transaction Does not influence COEX_GRANT.
COEX_STATUS0 Input Mandatory for 3-wire and 4-wire SR_STATUS Indicates if the Bluetooth LE/IEEE 802.15.4 transaction is TX or RX. If the device supports a Priority signal, Priority is muxed with TX/RX on this signal based on the timing diagrams. Does not influence COEX_GRANT.
COEX_GRANT Output Mandatory for 3-wire and 4-wire SR_GRANT Indicates that the Bluetooth LE/IEEE 802.15.4 device is granted access for this transaction. Only de-asserted during a Wi-Fi scan operation in the 2.4 GHz band.
COEX_STATUS1/SW_CTRL1 Input/Output Optional for 3-wire SR_PTI/RF_SW_CTRL1 In 4-wire mode, this carries the Bluetooth LE/IEEE 802.15.4 1 bit priority signal. In 3-wire Shared Antenna mode, this can be optionally used as a second antenna switch control signal. Does not influence COEX_GRANT in 4-wire mode. Can function as a second switch control signal in 3-wire mode.
SW_CTRL0 Output Mandatory for 3-wire and 4-wire Shared Antenna mode. Optional otherwise RF_SW_CTRL0 Used for antenna switch control in Shared Antenna mode. Functions as a switch control in Shared Antenna mode.
Note: The behavior of SW_CTRL0/1 is programmable and dependent on the configured coexistence mode and switch control interface.