Can't receive packets at 125Kbps

RE: Can't receive packets at 125Kbps

Grard — Mon, 13 Nov 2023 14:27:36 GMT

Yes, I am setting the first byte to 8:

As you can see, I do receive one byte (the length byte) but only that one and from time to time, the data is 0, I am sending every 500ms.

I expect to see the counter also in the receiver side, so that I know how many packets I've dropped.

# 0x8<<24 is the length of the packet, we can only have a counter up to 24 bits, no problem for tests
self.write_reg(REGS.PKT_BUFF_ADDRESS, 0x8 << 24 | pckt_counter)

This is the python code where I am loading the counter, this data is being copied to the buffer where the packet pointer is pointing at.

Kind regards,

Grard

EDIT: After further research I've found that this last issue is likely in the python side, so I believe it doesn't belong here anymore.

Thank you for your help! I really appreciate it.

Kind regards,

Grard

RE: Can't receive packets at 125Kbps

Håkon Alseth — Mon, 13 Nov 2023 14:13:27 GMT

Hi,

[quote user="Grard"]However, I do not get the content I expect, could it be that this data is shifted?[/quote]

Note that the first byte of the user payload is the length of the payload.

Do you have any example of expected vs. received data?

Kind regards,

Håkon

RE: Can't receive packets at 125Kbps

Grard — Mon, 13 Nov 2023 14:00:41 GMT

Hi Håkon,

Indeed I pasted the wrong configuration, with the one you linked to and some tweaks to adapt it to my code I am successfully receiving packets. However, I do not get the content I expect, could it be that this data is shifted? I am writing and reading from PACKETPTR in the same way I was doing with 802.15.4 PHY. Maybe I have to take into account other fields thar are not present in 802.15.4 PHY?

Thank you so much for your support,

Kind regards,

Grard

RE: Can't receive packets at 125Kbps

Håkon Alseth — Mon, 13 Nov 2023 13:07:18 GMT

Hi Grard,

Did you try the exact same configuration as posted in the thread that I linked to? You seem to have configurations specifically towards 802.15.4 PHY (CRC and channel-wise) at this time.

Kind regards,

Håkon

RE: Can't receive packets at 125Kbps

Grard — Fri, 10 Nov 2023 11:12:47 GMT

True! I fixed that but still can't receive, I've made some changes on the code:

static const nrf_radio_packet_conf_t radio_performance_packet_configuration = {
    .lflen = 8,
    .plen = 0x03,
    .crcinc = false,
    .maxlen = 128,
    .statlen = 0,
    .balen = 0,
    .big_endian = false,
    .whiteen = false,
};

And

void radio_performance_nrf52_rx_init(uint8_t channel) {

    if(channel < MIN_RADIO_CHANNEL_802_15_4 ||
       channel > MAX_RADIO_CHANNEL_802_15_4) {
        channel = MIN_RADIO_CHANNEL_802_15_4;
    }

    nrf_radio_power_set(false);
    nrf_radio_power_set(true);

    /* Disable all interrupts */
    nrf_radio_int_disable(0xFFFFFFFF);
    nrf_radio_mode_set(NRF_RADIO_MODE_BLE_LR125KBIT);
    nrf_radio_packet_configure(&radio_performance_packet_configuration);
    nrf_radio_modecnf0_set(true, RADIO_MODECNF0_DTX_Center);
    nrf_radio_crc_configure(RADIO_CRCCNF_LEN_Disabled, NRF_RADIO_CRC_ADDR_IEEE802154, 0x11021);
    nrf_radio_frequency_set(CHANNEL_TO_FREQ_802_15_4(channel));
    nrf_radio_shorts_enable(NRF_RADIO_SHORT_RXREADY_START_MASK |
                            NRF_RADIO_SHORT_END_DISABLE_MASK);

    nrf_radio_packetptr_set(nrf52_radio_buffer_rx);

    // Enable radio interrupts
    nrf_radio_int_enable(NRF_RADIO_INT_END_MASK);
    npl_freertos_hw_set_isr(RADIO_IRQn, nrf52RadioInterruptHandler);

    NVIC_SetPriority(RADIO_IRQn, 3);
    NVIC_ClearPendingIRQ(RADIO_IRQn);
    NVIC_EnableIRQ(RADIO_IRQn);
}

I have tried using IEEE802154 and it does work, changed the mode and the preamble to BLE 125kbit and it stopped receiving.

Sorry for bothering too much, I can't wrap my head around the issue.

Thank you, best regards.

Grard.

RE: Can't receive packets at 125Kbps

Håkon Alseth — Fri, 10 Nov 2023 09:05:30 GMT

Hi,

[quote user="Grard"]Thing is, I have read from this register right after configuring it by calling radio_performance_nrf52_rx_init as shown in my previous message, and loading up the radio_performance_packet_configuration which specifies that plen should be NRF_RADIO_MODE_BLE_LR125KBIT.[/quote]

PLEN only has 2 bits, and "NRF_RADIO_MODE_BLE_LR125KBIT" is defined to value '5'. This define is for the NRF_RADIO->MODE register, and not the PCNF0 register.

The side-effect of setting '5' here makes you set .CRCINC=1 as well, although you have specifically set this:

    nrf_radio_crc_configure(RADIO_CRCCNF_LEN_Three, NRF_RADIO_CRC_ADDR_SKIP, 0x11021);

You want to set it to "RADIO_PCNF0_PLEN_LongRange".

Kind regards,

Håkon

RE: Can't receive packets at 125Kbps

Grard — Fri, 10 Nov 2023 08:55:06 GMT

Hi, thank you for your answer,

PCNF0 is at 0x45410108, this is:

Apparently, PLEN is being set to 16 bit instead of BLE long range.

The other fields are indeed set to what I have configured in the packet_configuration structure

Thing is, I have read from this register right after configuring it by calling radio_performance_nrf52_rx_init as shown in my previous message, and loading up the radio_performance_packet_configuration which specifies that plen should be NRF_RADIO_MODE_BLE_LR125KBIT.

I will now read the post you linked to, maybe there is something that needs to be set in order to edit the preamble length?

Thank you for your help, it's really appreciated.

Kind regards,

Grard.

RE: Can't receive packets at 125Kbps

Håkon Alseth — Thu, 09 Nov 2023 14:41:28 GMT

Hi,

LR 125k isn't straight forward to configure, and will require a bit of "special care" compared to the other radio modes.

What is your PCNF0 register being set to? If you look at this thread, you can see other users that has had similar issues:

Bringing up 125Kbps Coded PHY on NRF52840

Kind regards,

Håkon