Minimizing ESB latency on nRF54L15

[Duccio]

Hi,
I’m currently experimenting with ESB using the standard esv_ptx/esb_prx examples on two nRF54L15 DK. My goal is to reduce the radio latency as much as possible. I'm still quite new to nordic devices.

I added some timing code using k_cycle_get_32() on the PTX side.
Right before calling esb_write_payload() I store the timestamp, and then I compute the difference when I receive ESB_EVENT_TX_SUCCESS.
With this method I get a round-trip-time of about 450 us for an 8 byte payload, with ACK enabled. However I’ve seen older threads where people get even lower values.

I would like to confirm if this is the right way to measure the RTT and if it's possible to reduce latency further?

I've noticed that unfortunatly the fast ramp option is only available for the nrf54h20.  Is there any alternative to achieve a faster ramp up on the nrf54L15?

Thanks in advance for your help!

[Håkon Alseth]

Hi,

 

With nRF52-series and newer, you can set:

config.use_fast_ramp_up = true;

 

without having CONFIG_ESB_FAST_SWITCHING enabled/set. Fast switching is a even reduced timing when doing turn-around (TX->RX or RX->TX) on nRF54-series devices.

 

I see that this is guarded in the samples at this time:

https://github.com/nrfconnect/sdk-nrf/blob/main/samples/esb/esb_ptx/src/main.c#L167-L169

 

However, this lacks a proper comment on why, which I will bring up internally with the ESB team.

 

Kind regards,

Håkon