How can I make nrf52832 talk to Microbit by RADIO (Gazell) ?

[Takashi]

I see that BBC Micro:bit uses nrf51822 and can use RADIO peripheral.

So I tried to make my nrf52832 DK to talk to Micro:bit by using Gazell library and referencing MicroBitRadio of Github.

(nrf5 SDK version is 14.0)

But it cannot get any data packet. (No "nrf_gzll_host_rx_data_ready" callback)

    #define MICROBIT_RADIO_BASE_ADDRESS 0x75626974
    
    // in main() function, I have added the followings before enable gazell.
    GAZELLE_ERROR_CODE_CHECK(nrf_gzll_set_base_address_0(MICROBIT_RADIO_BASE_ADDRESS));
    GAZELLE_ERROR_CODE_CHECK(nrf_gzll_set_address_prefix_byte(0, 0));// pipe, address_prefix_byte

How can I do this ? Is there any mistakes ?

I made a test code as the attached zip

by modifying \nRF5_SDK_14.0.0_3bcc1f7\examples\proprietary_rf\gzll\gzll_ack_payload\host.

Micro:bit code is here.

makecode.microbit.org/_EJJcxY5C2d6k

Other references:

github.com/.../MicroBitRadio.cpp

https://github.com/lancaster-university/microbit-dal/blob/master/inc/drivers/MicroBitRadio.h

https://tech.microbit.org/hardware/#low-level-radio-communications

host_test.zip

[Sigurd]

Hi,

The MicroBitRadio protocol might be gazell inspired, but it's not really 100% gazell and it also configures the RADIO differently than what gazell does in our SDK .(e.g. RADIO PCNF0/PCNF1 registers).

I got the gazell example to receive the microbit packets, here is the code i used(SDK15.2):

/**
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 *
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 *    Semiconductor ASA integrated circuit in a product or a software update for
 *    such product, must reproduce the above copyright notice, this list of
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 *
 * 3. Neither the name of Nordic Semiconductor ASA nor the names of its
 *    contributors may be used to endorse or promote products derived from this
 *    software without specific prior written permission.
 *
 * 4. This software, with or without modification, must only be used with a
 *    Nordic Semiconductor ASA integrated circuit.
 *
 * 5. Any software provided in binary form under this license must not be reverse
 *    engineered, decompiled, modified and/or disassembled.
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 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 *
 */
/**
 * This project requires that a device that runs the
 * @ref gzll_device_m_ack_payload_example is used as a counterpart for
 * receiving the data. This can be on either an nRF5x device or an nRF24Lxx device
 * running the \b gzll_device_m_ack_payload example in the nRFgo SDK.
 *
 * This example listens for a packet and sends an ACK
 * when a packet is received. The contents of the first payload byte of
 * the received packet is output on the GPIO Port BUTTONS.
 * The contents of GPIO Port LEDS are sent in the first payload byte (byte 0)
 * of the ACK packet.
 */
#include "nrf_gzll.h"
#include "bsp.h"
#include "app_timer.h"
#include "app_error.h"
#include "nrf_gzll_error.h"

#include "nrf_log.h"
#include "nrf_log_ctrl.h"
#include "nrf_log_default_backends.h"

/*****************************************************************************/
/** @name Configuration  */
/*****************************************************************************/
#define PIPE_NUMBER             0  /**< Pipe 0 is used in this example. */
#define TX_PAYLOAD_LENGTH       1  /**< 1-byte payload length is used when transmitting. */

#define MICROBIT_RADIO_MAX_PACKET_SIZE          32

static uint8_t                  m_data_payload[NRF_GZLL_CONST_MAX_PAYLOAD_LENGTH]; /**< Placeholder for data payload received from host. */
static uint8_t                  m_ack_payload[TX_PAYLOAD_LENGTH];                  /**< Payload to attach to ACK sent to device. */

#if GZLL_TX_STATISTICS
static nrf_gzll_tx_statistics_t m_statistics; /**< Struct containing transmission statistics. */
#endif

#if GZLL_PA_LNA_CONTROL

#define GZLL_PA_LNA_TIMER       CONCAT_2(NRF_TIMER, GZLL_PA_LNA_TIMER_NUM) /**< Convert timer number into timer struct. */

/**< PA/LNA structure configuration. */
static nrf_gzll_pa_lna_cfg_t m_pa_lna_cfg = {
    .lna_enabled        = GZLL_LNA_ENABLED,
    .pa_enabled         = GZLL_PA_ENABLED,
    .lna_active_high    = GZLL_LNA_ACTIVE_HIGH,
    .pa_active_high     = GZLL_PA_ACTIVE_HIGH,
    .lna_gpio_pin       = GZLL_PA_LNA_CRX_PIN,
    .pa_gpio_pin        = GZLL_PA_LNA_CTX_PIN,
    .pa_gpiote_channel  = GZLL_PA_LNA_TX_GPIOTE_CHAN,
    .lna_gpiote_channel = GZLL_PA_LNA_RX_GPIOTE_CHAN,
    .timer              = GZLL_PA_LNA_TIMER,
    .ppi_channels[0]    = GZLL_PA_LNA_PPI_CHAN_1,
    .ppi_channels[1]    = GZLL_PA_LNA_PPI_CHAN_2,
    .ppi_channels[2]    = GZLL_PA_LNA_PPI_CHAN_3,
    .ppi_channels[3]    = GZLL_PA_LNA_PPI_CHAN_4,
    .ramp_up_time       = GZLL_PA_LNA_RAMP_UP_TIME
};

static int32_t m_rssi_sum    = 0; /**< Variable used to calculate average RSSI. */
static int32_t m_packets_cnt = 0; /**< Transmitted packets counter. */
#endif


/**
 * @brief Function to read the button state.
 *
 * @return Returns states of the buttons.
 */
static uint8_t input_get(void)
{
    uint8_t result = 0;
    for (uint32_t i = 0; i < BUTTONS_NUMBER; i++)
    {
        if (bsp_button_is_pressed(i))
        {
            result |= (1 << i);
        }
    }

    return ~(result);
}


/**
 * @brief Function to control the LED outputs.
 *
 * @param[in] val Desirable state of the LEDs.
 */
static void output_present(uint8_t val)
{
    uint32_t i;

    for (i = 0; i < LEDS_NUMBER; i++)
    {
        if (val & (1 << i))
        {
            bsp_board_led_on(i);
        }
        else
        {
            bsp_board_led_off(i);
        }
    }
}


/**
 * @brief Initialize the BSP modules.
 */
static void ui_init(void)
{
    uint32_t err_code;

    // Initialize application timer.
    err_code = app_timer_init();
    APP_ERROR_CHECK(err_code);

    // BSP initialization.
    err_code = bsp_init(BSP_INIT_LEDS | BSP_INIT_BUTTONS, NULL);
    APP_ERROR_CHECK(err_code);

    // Set up logger.
    err_code = NRF_LOG_INIT(NULL);
    APP_ERROR_CHECK(err_code);

    NRF_LOG_DEFAULT_BACKENDS_INIT();

    NRF_LOG_INFO("Gazell ACK payload example. Host mode.");
    NRF_LOG_FLUSH();

    bsp_board_init(BSP_INIT_LEDS);
}


/*****************************************************************************/
/** @name Gazell callback function definitions.  */
/*****************************************************************************/
/**
 * @brief RX data ready callback.
 *
 * @details If a data packet was received, the first byte is written to LEDS.
 */
void nrf_gzll_host_rx_data_ready(uint32_t pipe, nrf_gzll_host_rx_info_t rx_info)
{
    uint32_t data_payload_length = NRF_GZLL_CONST_MAX_PAYLOAD_LENGTH;

    // Pop packet and write first byte of the payload to the GPIO port.
    bool result_value = nrf_gzll_fetch_packet_from_rx_fifo(pipe,
                                                           m_data_payload,
                                                           &data_payload_length);

    if (!result_value)
    {
        NRF_LOG_ERROR("RX fifo error ");
    }

    if (data_payload_length > 0)
    {
        output_present(m_data_payload[0]);
    }

    // Read buttons and load ACK payload into TX queue.
    m_ack_payload[0] = input_get(); // Button logic is inverted.

    result_value = nrf_gzll_add_packet_to_tx_fifo(pipe, m_ack_payload, TX_PAYLOAD_LENGTH);
    if (!result_value)
    {
        NRF_LOG_ERROR("TX fifo error ");
    }

#if GZLL_PA_LNA_CONTROL
    m_rssi_sum += rx_info.rssi;
    m_packets_cnt++;
#endif
}


/**
 * @brief Gazelle callback.
 * @warning Required for successful Gazell initialization.
 */
void nrf_gzll_device_tx_success(uint32_t pipe, nrf_gzll_device_tx_info_t tx_info)
{
}


/**
 * @brief Gazelle callback.
 * @warning Required for successful Gazell initialization.
 */
void nrf_gzll_device_tx_failed(uint32_t pipe, nrf_gzll_device_tx_info_t tx_info)
{
}


/**
 * @brief Gazelle callback.
 * @warning Required for successful Gazell initialization.
 */
void nrf_gzll_disabled()
{
}

#if GZLL_PA_LNA_CONTROL
/**
 * @brief Function for configuring front end control in Gazell.
 */
static bool front_end_control_setup(void)
{
    bool result_value = true;

    // Configure pins controlling SKY66112 module.
    nrf_gpio_cfg_output(GZLL_PA_LNA_CHL_PIN);
    nrf_gpio_cfg_output(GZLL_PA_LNA_CPS_PIN);
    nrf_gpio_cfg_output(GZLL_PA_LNA_ANT_SEL_PIN);
    nrf_gpio_cfg_output(GZLL_PA_LNA_CSD_PIN);

    // Turn on front end module.
    nrf_gpio_pin_clear(GZLL_PA_LNA_CHL_PIN);
    nrf_gpio_pin_clear(GZLL_PA_LNA_CPS_PIN);
    nrf_gpio_pin_clear(GZLL_PA_LNA_ANT_SEL_PIN);
    nrf_gpio_pin_set(GZLL_PA_LNA_CSD_PIN);

    // PA/LNA configuration must be called after @ref nrf_gzll_init() and before @ref nrf_gzll_enable()
    result_value = nrf_gzll_set_pa_lna_cfg(&m_pa_lna_cfg);

    return result_value;
}
#endif

/*****************************************************************************/
/**
 * @brief Main function.
 * @return ANSI required int return type.
 */
/*****************************************************************************/
#define NRF_GZLL_TEST_CHANNEL_TABLE_SIZE   1

#define MICROBIT_RADIO_BASE_ADDRESS 0x75626974

static uint8_t Test_chanel_table[] = {7};

static uint32_t swap_bits(uint32_t inp)
{
    uint32_t i;
    uint32_t retval = 0;

    inp = (inp & 0x000000FFUL);

    for (i = 0; i < 8; i++)
    {
        retval |= ((inp >> i) & 0x01) << (7 - i);
    }

    return retval;
}

static uint32_t bytewise_bitswap(uint32_t inp)
{
      return (swap_bits(inp >> 24) << 24)
           | (swap_bits(inp >> 16) << 16)
           | (swap_bits(inp >> 8) << 8)
           | (swap_bits(inp));
}


int main()
{
    // Set up the user interface.
    ui_init();

    // Initialize Gazell.
    bool result_value = nrf_gzll_init(NRF_GZLL_MODE_HOST);
    GAZELLE_ERROR_CODE_CHECK(result_value);

#if GZLL_PA_LNA_CONTROL
    // Initialize external PA/LNA control.
    result_value = front_end_control_setup();
    GAZELLE_ERROR_CODE_CHECK(result_value);
#endif

#if GZLL_TX_STATISTICS
    // Turn on transmission statistics gathering.
    result_value = nrf_gzll_tx_statistics_enable(&m_statistics);
    GAZELLE_ERROR_CODE_CHECK(result_value);
#endif

    // Load data into TX queue.
    m_ack_payload[0] = input_get();

    result_value = nrf_gzll_add_packet_to_tx_fifo(PIPE_NUMBER, m_data_payload, TX_PAYLOAD_LENGTH);
    if (!result_value)
    {
        NRF_LOG_ERROR("TX fifo error ");
        NRF_LOG_FLUSH();
    }

    //Edit
    nrf_gzll_set_channel_table(Test_chanel_table,NRF_GZLL_TEST_CHANNEL_TABLE_SIZE);
    GAZELLE_ERROR_CODE_CHECK(nrf_gzll_set_base_address_0(bytewise_bitswap(0x74696275)));
    GAZELLE_ERROR_CODE_CHECK(nrf_gzll_set_address_prefix_byte(0, 0));// pipe, address_prefix_byte
    GAZELLE_ERROR_CODE_CHECK(nrf_gzll_set_datarate(NRF_GZLL_DATARATE_1MBIT));


    // Enable Gazell to start sending over the air.
    result_value = nrf_gzll_enable();
    GAZELLE_ERROR_CODE_CHECK(result_value);


        //Edit
        NRF_RADIO->PCNF0 = 0x00000008;
        NRF_RADIO->PCNF1 = 0x02040000 | MICROBIT_RADIO_MAX_PACKET_SIZE;
        NRF_RADIO->DATAWHITEIV = 0x18;
    
    NRF_LOG_INFO("Gzll ack payload host example started.");

    while (true)
    {
        NRF_LOG_FLUSH();
        __WFE();

#if GZLL_PA_LNA_CONTROL
        if (m_packets_cnt >= 1000)
        {
            CRITICAL_REGION_ENTER();

            // Print info about average RSSI.
            NRF_LOG_RAW_INFO("\r\n");
            NRF_LOG_INFO("Average RSSI: %d", (m_rssi_sum / m_packets_cnt));
            m_packets_cnt = 0;
            m_rssi_sum    = 0;

            CRITICAL_REGION_EXIT();
        }
#endif

#if GZLL_TX_STATISTICS
        if (m_statistics.packets_num >= 1)
        {
            CRITICAL_REGION_ENTER();

            // Print all transmission statistics.
            NRF_LOG_RAW_INFO("\r\n");
            NRF_LOG_INFO("Total received packets:   %4u", m_statistics.packets_num);
            NRF_LOG_INFO("Total CRC failures:       %03u\r\n", m_statistics.timeouts_num);

            for (uint8_t i = 0; i < nrf_gzll_get_channel_table_size(); i++)
            {
                NRF_LOG_INFO("Channel %u: %03u packets received, %03u CRC failures.",
                             i,
                             m_statistics.channel_packets[i],
                             m_statistics.channel_timeouts[i]);
            }

            CRITICAL_REGION_EXIT();

            // Reset statistics buffers.
            nrf_gzll_reset_tx_statistics();
        }
#endif
    }
}

That said, it might be better for you to use ESB or the radio directly.

[Takashi]

Thank you so much. It works perfectly.