RE: ncs 3.3.0: Achieve non-concurrent switching between ESB/BLE

stak — Mon, 03 Aug 2026 13:07:37 GMT

ESB Fast Switching on the nRF54L15 isn't supported yet in the SDK. So, ESB and BLE cannot run concurrently on the same radio. ESB requires exclusive use of the radio (NRF_RADIO), while BLE is managed by the SoftDevice Controller via MPSL.

The dynamic-interrupt options in your config (CONFIG_ESB_DYNAMIC_INTERRUPTS, CONFIG_MPSL_DYNAMIC_INTERRUPTS, etc.) allow runtime IRQ handover, but they do not enable true simultaneous operation. That is why pairing works when ESB is disabled, and fails when ESB is enabled.

Some configuration notes:

Remove CONFIG_ESB_FAST_SWITCHING and CONFIG_ESB_FAST_CHANNEL_SWITCHING — these are for nRF54H20 only, not nRF54L15.
CONFIG_ESB_CLOCK_INIT — not a valid nCS Kconfig option?
Avoid forcing CONFIG_ESB_RADIO_IRQ_PRIORITY=0 unless strictly needed; default values are recommended.

If you want to use both ESB and BLE in the same product, the radio must be time-sliced in application code. You can switch between BLE and ESB by disable/re-init the two:

bt_disable() — this calls mpsl_lib_uninit() and cleans up MPSL/BLE radio usage
esb_init() — ESB takes over the radio interrupts
When ESB is finished: esb_disable()
To return to BLE: bt_enable() — MPSL/BLE reclaim the radio

esb_init() installs ESB’s radio (and related) interrupt handlers. If MPSL has not been properly cleaned up/uninitialized first, ESB can receive unexpected radio interrupts because both stacks may contend for the same IRQ path.

Stine

RE: ncs 3.3.0: Achieve non-concurrent switching between ESB/BLE

stak — Mon, 03 Aug 2026 07:48:32 GMT

Hi John,

I’m looking into this. I will come back to you asap.

Stine