Radio timing nrf24l01+ and nrf52832

RE: Radio timing nrf24l01+ and nrf52832

Kenneth — Wed, 10 Jul 2019 08:34:49 GMT

It seems that many of the timing data for the "legacy" modes are missing from the nRF52 datasheet, however since they are backwards compatible you may indirectly find some of the missing timing details in the nRF24L01+ datasheet:

https://infocenter.nordicsemi.com/pdf/nRF24L01P_PS_v1.0.pdf?cp=8_4_0_0

For instance figure 17.

RE: Radio timing nrf24l01+ and nrf52832

aeq — Tue, 09 Jul 2019 13:59:04 GMT

I think that TIFS is not used in non BLE mode. The reset value of this register is 0 and in ESB code for example it is not used. So I think that the delay is somehow hardwired in the HW. I just want to know how it is done by RADIO peripheral.

RE: Radio timing nrf24l01+ and nrf52832

Kenneth — Tue, 09 Jul 2019 13:42:03 GMT

Some of these timings are found here:

https://infocenter.nordicsemi.com/topic/com.nordic.infocenter.nrf52832.ps.v1.1/radio.html?cp=3_1_0_22_14_7#unique_1399037651

But for non-BLE modes the TIFS is 130us, while for BLE modes it is 150us.

RE: Radio timing nrf24l01+ and nrf52832

aeq — Mon, 08 Jul 2019 15:08:47 GMT

Thanks for your reply, but my question is not about using BLE mode with ESB, as I wrote above, I am interested in RADIO peripheral behavior, and why it is able to communicate successfully in the configuration described. I am asking about timings of RADIO peripheral in RADIO_MODE_MODE_Nrf_250Kbit, RADIO_MODE_MODE_Nrf_1Mbit or RADIO_MODE_MODE_Nrf_2Mbit and with RADIO_SHORTS_READY_START_Msk, RADIO_SHORTS_END_DISABLE_Msk and RADIO_SHORTS_DISABLED_RXEN_Msk set on the TX side and RADIO_SHORTS_READY_START_Msk, RADIO_SHORTS_END_DISABLE_Msk and RADIO_SHORTS_DISABLED_TXEN_Msk on the RX side.

RE: Radio timing nrf24l01+ and nrf52832

Kenneth — Mon, 08 Jul 2019 14:12:07 GMT

The difference between (legacy ESB mode, aka nRF24L) and BLE mode:

1. Radio switching time increased from 130us (ESB) to 150us (BLE).

2. GFSK deviation increased from 170kHz (ESB) to 250kHz (BLE).

They are somewhat on-air compatible because similar timing and modulation, but not recommended to mix the two modes because they are not designed or tested to be compatible.

Best regards,
Kenneth

RE: Radio timing nrf24l01+ and nrf52832

aeq — Fri, 05 Jul 2019 13:10:22 GMT

Yes, I know about this register. The data sheet says that it is to be used in BLE mode, and any way it is not used in ESB implementation for nrf52 and any other protocol implementation that I saw. The radio seems to be working with a configuration I described above, and what am I interested in is why it works. It seems that there is an additional delay in RX to TX switching with shortcuts. I am looking for a confirmation of this or some description of the radio timings with shortcuts set as I wrote above.

RE: Radio timing nrf24l01+ and nrf52832

run_ar — Fri, 05 Jul 2019 10:48:49 GMT

Did you look at the TIFS register?

Inter Frame Spacing in us

Inter frame space is the time interval between two consecutive packets. It is defined as the time, in micro seconds, from the end of the last bit of the previous packet to the start of the first bit of the subsequent packet.

RE: Radio timing nrf24l01+ and nrf52832

aeq — Wed, 26 Jun 2019 22:21:56 GMT

Any help, please)

RE: Radio timing nrf24l01+ and nrf52832

aeq — Mon, 24 Jun 2019 14:44:42 GMT

Hi,

Thanks for your reply. I read carefully the Backward compatibility section and the whole document, also I checked the sources (nrf_esb.c) from SDK 15.3 but did not find the answer. My question is not about ESB it self I think it's more about the RADIO peripheral. So we set RADIO_SHORTS_READY_START_Msk, RADIO_SHORTS_END_DISABLE_Msk and RADIO_SHORTS_DISABLED_RXEN_Msk on the PTX side. This makes it switch to rx state to receive ack packet as fast as possible after it finishes TX. And this time to switch from tx to rx is (TX disabled) + (RX enabled) + (RX PLL rump up), right? Then on the PRX side we set RADIO_SHORTS_READY_START_Msk, RADIO_SHORTS_END_DISABLE_Msk and RADIO_SHORTS_DISABLED_TXEN_Msk and the time required to switch to TX after RX is (RX disabled) + (TX enabled) + (TX PLL rump up), right? This time values seems to be equal (or the PTX time is even lager), so the PRX may start to tx ack packet faster then the PTX is ready to receive it? Or is there a mechanism in the RADIO peripheral to prevent this situation, maybe some kind of delay when switching between RX and TX to make it for sure longer then TX to RX? I did not find any information on this case in datasheet or online documentation.

Thanks for any information or explanation on this case.

RE: Radio timing nrf24l01+ and nrf52832

run_ar — Mon, 24 Jun 2019 11:35:18 GMT

Hi,

Please refer to the compatibility chapter for ESB here: Backward compatibility