Radio PCNF1 register settings

Question

Hello ! 
 1. In some legacy code I have found that radio channel is configured twice 
 
 NRF_RADIO -> FREQUENCY = channel; 
 
 NRF_RADIO -> DATAWHITEIV = channel; 
 
 Can it be some tail from some old fixes of some anomalies ? 
 
 in our system Data-whitening is configured once via PCNF1 register once. 
 
 I think this line NRF_RADIO->DATAWHITEIV need to be deleted. 
 
 2. In my system I should receive short 64 byte frame and after that after some microseconds - long 255 byte frame. 
 
 Can I update MAXLEN value in PCF1 register so often. e.g every ime when I initiate RX or TX operation ? e.g every 1-2 ms ? 
 
 If MAXLEN is set to 255, I can suddenly receive long frame and it ruin my timing. 
 
 If receiving started, it should take 64 bytes and generate END event. 
 
 Are any problems to update MAXLEN so often ?

Eugene

Jørgen Holmefjord · Accepted Answer

Hiihtaja said: some splitting for address what need to be written to BASE0 and BASE1 registres. 
 On practice everybody use standard BLE address or IEEE specific one. 
 
 But what address range can be used if we would like to be as far as possible from known standard radios 
 You should be able to select any address not used by BLE or one of the other known protocols. However, you should follow these guidelines: 
 
 In general it is bad practice to start an address with either 0x00, 0xFF, 0xA or 0x5. 0x00 and 0xFF because they contain no bit shifts, and 0xA or 0x5 because they form a continuation of the preamble (the preamble is either 0xAA or 0x55). 
 
 IEEE 802.15.4 does not use the address fields, as you can see from Receive sequence . It uses a preamble with synchronization header. IEEE 802.15.4 also uses different modulation, datarate, and channels than BLE/proprietary modes. 
 Hiihtaja said: Basically packets what have different addresses are rejected without any extra events and do not generate any RX not OK or wrong CRC .e.g without any events. BUT they still occupy time slot, 
 our packet interfere to other packet and packet will be corrupted or not even received. 
 If the other protocol transmits the packet on-air at the exact same time as your protocol, there is chance that the signal will interfere anyways, preventing you from receiving the packet correctly. 
 The radio will only start receiving a packet once it gets an address match, meaning other protocols will not "take time" from your radio. Only when a valid address is detected, the radio will continue receiving the payload and check CRC, etc. 
 Hiihtaja said: What about Wifi ? Is any BLE registers can have special values what minimize impact from it ? 
 Wifi uses different modulation, datarate, and channels. The on-air signals may interfere with your wanted signal, but it should normally not cause address matches in the radio. BLE have placed advertising channels on the outside of most used WiFi channels, and implements frequency hopping on connections, to limit impact from other protocols/signals.

Radio PCNF1 register settings

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