Radio 2.4 Ghz, Enable Fast mode in Rx and Tx

[vasilje]

Hi,

How to enable fast mode for radio transmission and reception (I am using nRF5 SDK). These are the default examples and I can see that fast mode is not implemented:

Reception:

uint32_t read_packet(uint32_t* packet)
{
    memset((uint8_t*)packet, 0, CUSTOM_PACKET_STATIC_LENGTH);

    NRF_RADIO->PACKETPTR = (uint32_t)packet;
    uint32_t result = !NRF_SUCCESS;

    NRF_RADIO->EVENTS_READY = 0U;
    // Enable radio and wait for ready
    NRF_RADIO->TASKS_RXEN = 1U;

    while (NRF_RADIO->EVENTS_READY == 0U)
    {
        // wait
    }
    NRF_RADIO->EVENTS_END = 0U;
    // Start listening and wait for address received event
    NRF_RADIO->TASKS_START = 1U;

    // Wait for end of packet or buttons state changed
    while (NRF_RADIO->EVENTS_END == 0U)
    {
        // wait
    }

    if (NRF_RADIO->CRCSTATUS == 1U || packet[0]!=0)
    {
        //Packet received with CRC ok or just received some data
        result = NRF_SUCCESS;
    }

    NRF_RADIO->EVENTS_DISABLED = 0U;
    // Disable radio
    NRF_RADIO->TASKS_DISABLE = 1U;

    while (NRF_RADIO->EVENTS_DISABLED == 0U)
    {
        // wait
    }
    return result;
}

Transmission:

 void send_packet(uint32_t* packet)
{
    uint32_t err_code = NRF_SUCCESS;
    // Set payload pointer
    NRF_RADIO->PACKETPTR = (uint32_t)packet;
    // send the packet:
    NRF_RADIO->EVENTS_READY = 0U;
    NRF_RADIO->TASKS_TXEN   = 1;
    // NRF_LOG_INFO("Waiting for ready");
    while (NRF_RADIO->EVENTS_READY == 0U)
    {
        // wait
    }
    NRF_RADIO->EVENTS_END  = 0U;
    NRF_RADIO->TASKS_START = 1U;
    // NRF_LOG_INFO("Prepare sending");
    while (NRF_RADIO->EVENTS_END == 0U)
    {
        // wait
    }
    // NRF_LOG_INFO("Done sending");
    
    err_code = bsp_indication_set(BSP_INDICATE_SENT_OK);
    APP_ERROR_CHECK(err_code);

    // NRF_LOG_INFO("The packet was sent");

    NRF_RADIO->EVENTS_DISABLED = 0U;
    // Disable radio
    NRF_RADIO->TASKS_DISABLE = 1U;

    while (NRF_RADIO->EVENTS_DISABLED == 0U)
    {
        // wait
    }
}

Would really appreciate some help.

[Jørgen Holmefjord]

Hi,

When you say fast mode, are you referring to the Fast ramp-up configuration? This can be enabled in the MODECNF0 register, by writing LSB to 1:

NRF_RADIO->MODECNF0 |= 1;

Best regards,
Jørgen

[vasilje]

Hi,

I am not sure, whatever will help make it faster. I wanted to get to timing of 40us:

I think its also related to shorting the Start and Ready; END and Disable:

[Jørgen Holmefjord]

Ok, then my previous answer is valid for answering your question.

[vasilje]

And what about READY_START in SHORTS for example?

[Jørgen Holmefjord]

Enabling the SHORT will not affect the time between TXEN task and READY event (the 40 us from spec), but it will possibly shorten the time between READY event and START task if this is desirable in your application.