Does the nrf52832 has some delay when the shortcut of END_START is enabeled in continuous receiving?What is the meaning of rx chain delay?Does RX chain delay in 2Msps mode is 5us or 9.4us?

[jane_song]

Does the nrf52832 has some delay when the shortcut of  END_START is enabeled in continuous receiving?What is the meaning of rx chain delay?Does RX chain delay in 2Msps mode is 5us or 9.4us?

[Andreas]

Hi,

 

Unfortunately we do not have any numbers for this, I would expect it to be <1 µs. t_RXCHAIN is the time from a bit appears as energy on the ANT pin to the radio peripheral is aware of it, so that is not relevant.

 

Best regards,

Andreas

[jane_song]

Hi,
Thanks!Before I post the questions,I also browse some related Q&A.Some descriptions about rx chain delay seem differen as yours.Here are some links:
devzone.nordicsemi.com/.../what-is-rx-tx-chain-delay
devzone.nordicsemi.com/.../113978
Someone said: In other words you should be fine as long as there is a 10us delay between the end of the CRC of the first packet, and the start of the address of the second packet.
I'm so confused about the exact that.

[Andreas]

Hi,

 

No, this is the same but just a different explanation. For RX: if the first bit of the second packet appears on the antenna appears on the antenna immediately after the last bit of the CRC has been processed in the radio, it will take ~10µs (t_RXCHAIN) before the first bit makes it into the radio digital part.

 

Best regards,

Andreas

[jane_song]

Hi,

   Thanks.When choosing Nrf_2Mbit mode, does the exact  RX chain delay  is 5us or 9.4us?

[Andreas]

Hi,

 

nRF_2Mbps mode shares the typical 5µs RX chain delay with the BLE2_Mbps mode. nRF_1Mbps and BLE_1Mbps has typical 9.4 µs RX chain delay.

 

Best regards,

Andreas

[jane_song]

Hi,

  Thanks!As we all known,the tx or rx chaian delay is the delay between consecutive transmitting or receiving packets.TX chain delay is only 0.6us,however RX chain delay is 5us in 2Mbps.So when we transmit packests with 1us interframe spacing,the rx side can not dealing with the packets successfully.In other words,the least interframe spacing time must  be 5us to insure that consecutive packets can be receiving successfully.

[Andreas]

Hi,

 

Not quite. You can retransmit a packet to the nRF52 with 1µs interframe spacing, but the packet will not 'reach' the digital part of the radio receiver before after 5µs.

 

Best regards,

Andreas

[jane_song]

Hi,

  Thanks a lot!

  I use one nrf52 chip to transmit consecutive packets with 1us interframe spacing in 2Mbps mode and use a timer to collect all end times for compare.The RX chip can receive the packets with the whole rx chain delay 5us and packets with 1us spacing.

   Now I have another question:when several chips transmit packets one by one,should they have a inter spacing?Or just as the one chip transmitting consecutive packets ?

  I'm looking forward your reply.Because it is important for my future developement.If there must be some inter spacing time  among serveral chips,I must add the spacing time between consecutive packets from different chips. 

[Andreas]

Hi,

 

If I understand correctly you should probably add the 5µs delay between the transmitted packets just so that you are certain the receiver is ready for the next one. (I am not 100% sure how it likes to receive two packets within the same receive event) Feel free to try sending without any interspacing though, it might work and you will not break anything.

 

Best regards,

Andreas

[jane_song]

Hi,

   Thanks a lot!Maybe my description is not clear to understand.I already use one nrf52 chip to transmit consecutive packets with 1us interframe spacing in 2Mbps mode,and the receiver can  receive the the first packet is delayed to 5us and the following packets with 1us interframe spacing.The diagram is as below:

However,when I use four different tx chips with the interframe spacing (1us ~ 10us)，the receiver can not succeed in receiving all the packets.So my main trouble is the difference between one chip and several chips when sending consecutive packets.Is the tx end the same tine with the receive end besides rx whole rx chain delay?