nRF70 Series PTA-based coexistence

The nRF70 Series devices offer highly configurable coexistence hardware to help mitigate interference between Wi-Fi® and devices like Bluetooth® LE, Thread®, and Zigbee®.

The coexistence hardware for the nRF70 Series has a Packet Traffic Arbitration (PTA) module connected to coexistence hardware logic functions that facilitate mitigating various interference scenarios through a highly programmable fabric. This enables flexible output signals supporting multiple interface configurations such as:

3-wire interface without multiplexed PRIORITY signal
3-wire interface with multiplexed PRIORITY signal
4-wire interface

Figure 1. Interface configuration

The following are supported antenna configurations:

Shared Antenna mode—The PTA makes priority decisions and controls the switch between Bluetooth LE/IEEE 802.15.4 and Wi-Fi. The PTA also grants TX/RX requests from the Bluetooth LE/IEEE 802.15.4 device. Only one interface, either Bluetooth LE/IEEE 802.15.4 or Wi-Fi, is connected to the antenna at any time.
Separate Antenna mode—The PTA makes priority decisions, granting TX/RX requests from Bluetooth LE/IEEE 802.15.4. Each interface is permanently connected to its own antenna.

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

Figure 2. Coexistence hardware architecture

Table 1. Coexistence hardware signals
Signal name	I/O	Mandatory/Optional	Bluetooth LE/IEEE 802.15.4 signal (3-wire/4-wire)	Description
COEX_REQ	Input	Mandatory for 3-wire and 4-wire	SR_REQUEST	Bluetooth LE/IEEE 802.15.4 device requesting a TX/RX transaction.
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, it is multiplexed with TX/RX on this signal.
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.
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.
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.

Note: The behavior of SW_CTRL0/1 is programmable and dependent on the configured coexistence mode and switch control interface.