Enabling Data Whitening for ESB Data Communication

[shchu]

I have one TX and another RX codes for data communication by ESB protocol. To verify whether data whitening can be enabled, I added below register setting on TX side only and let RX side use its default setting (data whitening disabled):

NRF_RADIO->PCNF1 = ((NRF_RADIO->PCNF1 & ~RADIO_PCNF1_WHITEEN_Msk) | (RADIO_PCNF1_WHITEEN_Enabled << RADIO_PCNF1_WHITEEN_Pos))

NRF_RADIO->DATAWHITEIV = 0x55

I expect the RX side should receive nothing from TX for this experiment but the RX could still receive all the packets (no CRC error) from TX without any packet drop. It looks like the data whitening was not working.

Does the ESB support data whitening? If yes, what is wrong with my setting? Thanks.

[Kenneth]

Have you checked the packet content? I would assume that CRC is calculated over the packet content, and thereby be valid depending on the content (with or without data whitening), the actual data however may be whitened.

Best regards,
Kenneth

[shchu]

Yes, I checked the packet content on RX. No data whitening on them after received.

You are right for the CRC check. I misunderstand it.

Any other reasons? Data whitening not worked on TX?

[Kenneth]

Hmm.. it may only work in BLE mode?

http://infocenter.nordicsemi.com/topic/com.nordic.infocenter.nrf52832.ps.v1.1/radio.html?cp=2_1_0_22_13_10#register.MODE 

Can you give that a try also?

[shchu]

To test BLE from ESB mode, it should not simply change the MODE register's value from 1 (Nrf_2Mbit) to 4 (Ble_2Mbit), right?

As our TX & RX codes were already associated with some feature functions by us, it is not easy and fastly to change to BLE if not just a change in the MODE register's value.

But I guess the data whitening function can be both applied to BLE and ESB if according to the radio block disgram of figure 1 below

http://infocenter.nordicsemi.com/index.jsp?topic=%2Fcom.nordic.infocenter.nrf52832.ps.v1.1%2Fradio.html&anchor=concept_lhd_ygj_4r__fig

Any suggestion?

Thank you so much

[Kenneth]

This is just a test setup, so my suggestion is for test that you set MODE to BLE_1MBit on both PRX and PTX. No other change should be required for test. Then you can try to enable data whitening on the PTX, to check if PRX still receive the correct data.

Thanks,
Kenneth