[243] RADIO: T_IFS is inaccurate with Bluetooth Long Range

This anomaly applies to Revision 2, build codes CKAA-Dx0, QIAA-Dx0.

It was inherited from the previous IC revision Engineering D.

Symptoms

The measured T_IFS is inaccurate for LE Coded PHY.

Conditions

Using default values of the TIFS register.

Consequences

T_IFS does not meet the accuracy required by the Bluetooth specification.

Workaround

Depending on the mode of the received packet and the mode selected for the next transmission, update the TIFS register with the following values:
  • RX: mode 6 (S=2), TX: mode 6 (S=2) : 144
  • RX: mode 5 (S=8), TX: mode 5 (S=8) : 149
  • RX: mode 5 (S=8), TX: mode 6 (S=2) : 139
  • RX: mode 6 (S=2), TX: mode 5 (S=8) : 154
The TIFS register must be updated before the DISABLED event from the receive packet. Otherwise, the new value is not taken into account for the next transmission. The rate of the last received packet can be found in the CISTAT field of the PDUSTAT register. The CISTAT field is updated approximately 1 ┬Ás after the ADDRESS event. The SoftDevice, Zephyr Controller subsystem (Zephyr and nRF Connect SDK), and SoftDevice Controller subsystem (nRF Connect SDK) are not affected by this errata.