ESB with different frequency

[Vlad Mokhnachov]

Hi! I have used NRF52832 on PCA10040. I want use several pair (master and slave) in one room. For this I try to select a different frequency for each pair. But, when I try to make this, I have some problem.

Case: one ESB master and one ESB slave. Master send always packet at channel 2 (2402 MHz). Slave listen each channel 25ms and after make a list of all frequencies with received packets and average RSSI.

• Channel = 1; Count Packet = 76; RSSI = 31
• Channel = 2; Count Packet = 79; RSSI = 23
• Channel = 3; Count Packet = 78; RSSI = 22
• Channel = 18; Count Packet = 3; RSSI = 80
• Channel = 50; Count Packet = 7; RSSI = 78
• Channel = 51; Count Packet = 1; RSSI = 78
• Channel = 66; Count Packet = 49; RSSI = 75
• Channel = 67; Count Packet = 20; RSSI = 73
• Channel = 90; Count Packet = 44; RSSI = 74

How it is possible? And what strategy of selecting channels can I used for normal working of all pairs?

[butch]

Have you considered using an address? Each pair use a distinct address. I am not very familiar with ESB or RF channel crosstalk.

[Vlad Mokhnachov]

NRF_RADIO->FREQUENCY = m_esb_addr.rf_channel;

My test work without pair, but I want use different channel for each pair. For example: pair1 at 2-th channel, pair2 at 36-th, etc.

[butch]

We are not understanding each other. The address is different from the rf channel. An address is an ID that is sent in the payload. You tell the receiver what addresses to match. If an OTA packet does not contain the address in the payload, the receiver ignores the OTA packet. I could be wrong, maybe ESB doesn't provide address matching capability. But in general, the Nordic radio does.

[butch]

So each pair would have a unique (rfchannel, addr.) There would still be crosstalk between the rf channels, but the addresses would not match. If your question is: why is there so much crosstalk, I can't answer that.

[Vlad Mokhnachov]

All pairs use logical address(pipe) for self. I can't give different pipe for each pair, unfortunately.