RF51822 packet loss can't recover

[D-Nordic]

Hi Nordic

I am using ESB_DPL protocol between two 51822 to do RF communication.

First i put two device very close, works very good, no packet loss, then I moved the TX device to 2m away, found there are some packet loss, then I moved back the TX device (very close to RX device again), but packet loss still happens, i need to reboot the TX device again to recover.

I did some small change with example esb_ptx in proprietary_rf, see below code. The protocol is ESB_DPL and disabled ack(.selective_auto_ack = true and .noack= true), the packet size is 64Byte. Why this happens? Could you give some suggestions? Thanks

Configuration:

nrf_esb_config_t nrf_esb_config         = NRF_ESB_DEFAULT_CONFIG;
nrf_esb_config.protocol                 = NRF_ESB_PROTOCOL_ESB_DPL;
nrf_esb_config.retransmit_count         = 0;
nrf_esb_config.retransmit_delay         = 250;
nrf_esb_config.bitrate                  = NRF_ESB_BITRATE_250KBPS;
nrf_esb_config.event_handler            = nrf_esb_event_handler;
nrf_esb_config.selective_auto_ack       = true;
nrf_esb_config.tx_output_power          = NRF_ESB_TX_POWER_4DBM;
nrf_esb_config.event_irq_priority       = 1;
nrf_esb_config.radio_irq_priority       = 2;
nrf_esb_config.mode                     = NRF_ESB_MODE_PTX;

Send packet:

        rf_tx_payload.length = spi_rx_buf[1];           /**< Length of the packet. 
        rf_tx_payload.pipe=0;                             /**< Pipe used for this payload. */
        rf_tx_payload.rssi=0;                           /**< RSSI for received packet. */
        rf_tx_payload.noack= true;                   //this packet will not be acknowledged
        rf_tx_payload.pid=0;                          /**< PID assigned during communication. */
        for(index=0;index<spi_rx_buf[1];index++)
        {
            rf_tx_payload.data[index]=spi_rx_buf[2+index];
        }            
        nrf_esb_write_payload(&rf_tx_payload);
        nrf_esb_write_payload(&rf_tx_payload);

[Hung Bui]

Could you let me know which SDK version you are using ? If you use selective ACK and set noack= true, I don't think you will receive NRF_ESB_EVENT_TX_FAILED. With uESB we will already return NRF_ESB_EVENT_TX_SUCCESS if there is no ACK required. It's pretty straight forward, if you don't expect ACK how could you know the packet will be success or not ? You will always assume the packet is successfully transmitted.

[D-Nordic]

SDK version is nRF5_SDK_11.0.0_89a8197

Yes, i want the channel to be fully used by TX->RX, so don't expect ACK, and the receiver will discard the useless packet.

Another question is sometimes the received data are all zero.

[Hung Bui]

I assume you find packet loss by checking on the RX side ? since it's always success on TX side.

Note that there could be interference from other devices, such as wifi, you should try to test with different channels.

Please try to test with the default example in the SDK and let us know if you observe the same thing. In addition, please send your schematic and layout of your boards.

[D-Nordic]

I want to send the packet with 1ms space, and don't want to use delay(nrf_delay_ms(1)) because if so mcu can't do other things, can I use timer? How to use timer in RF51822.

Another question: From the SDK sample, we can config 125 channels, but what's the corresponding frequency?

[Hung Bui]

Please focus on the topic in the question. If you have other questions, open another case.