RE: nRF52832 + ESP32 connection

haakonsh — Mon, 24 Jan 2022 14:32:51 GMT

Connect the proper wires and the SPI event handler will print the content of the RX buffer as long as the first bye is non-zero.

RE: nRF52832 + ESP32 connection

pgonzaleztrucorp — Mon, 24 Jan 2022 14:09:49 GMT

I flashed it and connected it to a terminal. Without connecting the ESP32 I can see "<info> app: Transfer completed." all the time.

Now, what do I have to do in order to receive data from the ESP32?

RE: nRF52832 + ESP32 connection

haakonsh — Mon, 24 Jan 2022 12:06:56 GMT

looks like the nrfx example does not build for the nRF52832 out of the box, so instead, I want you to use the SPI Master Example.

For reference here's the main.c file:

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 * 1. Redistributions of source code must retain the above copyright notice, this
 *    list of conditions and the following disclaimer.
 *
 * 2. Redistributions in binary form, except as embedded into a Nordic
 *    Semiconductor ASA integrated circuit in a product or a software update for
 *    such product, must reproduce the above copyright notice, this list of
 *    conditions and the following disclaimer in the documentation and/or other
 *    materials provided with the distribution.
 *
 * 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.
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 *    Nordic Semiconductor ASA integrated circuit.
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#include "nrf_drv_spi.h"
#include "app_util_platform.h"
#include "nrf_gpio.h"
#include "nrf_delay.h"
#include "boards.h"
#include "app_error.h"
#include <string.h>
#include "nrf_log.h"
#include "nrf_log_ctrl.h"
#include "nrf_log_default_backends.h"

#define SPI_INSTANCE  0 /**< SPI instance index. */
static const nrf_drv_spi_t spi = NRF_DRV_SPI_INSTANCE(SPI_INSTANCE);  /**< SPI instance. */
static volatile bool spi_xfer_done;  /**< Flag used to indicate that SPI instance completed the transfer. */

#define TEST_STRING "Nordic"
static uint8_t       m_tx_buf[] = TEST_STRING;           /**< TX buffer. */
static uint8_t       m_rx_buf[sizeof(TEST_STRING) + 1];    /**< RX buffer. */
static const uint8_t m_length = sizeof(m_tx_buf);        /**< Transfer length. */

/**
 * @brief SPI user event handler.
 * @param event
 */
void spi_event_handler(nrf_drv_spi_evt_t const * p_event,
                       void *                    p_context)
{
    spi_xfer_done = true;
    NRF_LOG_INFO("Transfer completed.");
    if (m_rx_buf[0] != 0)
    {
        NRF_LOG_INFO(" Received:");
        NRF_LOG_HEXDUMP_INFO(m_rx_buf, strlen((const char *)m_rx_buf));
    }
}

int main(void)
{
    bsp_board_init(BSP_INIT_LEDS);

    APP_ERROR_CHECK(NRF_LOG_INIT(NULL));
    NRF_LOG_DEFAULT_BACKENDS_INIT();

    nrf_drv_spi_config_t spi_config = NRF_DRV_SPI_DEFAULT_CONFIG;
    spi_config.ss_pin   = SPI_SS_PIN;
    spi_config.miso_pin = SPI_MISO_PIN;
    spi_config.mosi_pin = SPI_MOSI_PIN;
    spi_config.sck_pin  = SPI_SCK_PIN;
    APP_ERROR_CHECK(nrf_drv_spi_init(&spi, &spi_config, spi_event_handler, NULL));

    NRF_LOG_INFO("SPI example started.");

    while (1)
    {
        // Reset rx buffer and transfer done flag
        memset(m_rx_buf, 0, m_length);
        spi_xfer_done = false;

        APP_ERROR_CHECK(nrf_drv_spi_transfer(&spi, m_tx_buf, m_length, m_rx_buf, m_length));

        while (!spi_xfer_done)
        {
            __WFE();
        }

        NRF_LOG_FLUSH();

        bsp_board_led_invert(BSP_BOARD_LED_0);
        nrf_delay_ms(200);
    }
}

I want you to change line 57 from "static uint8_t m_rx_buf[sizeof(TEST_STRING) + 1]; /**< RX buffer. */" to:
"static uint8_t m_rx_buf["size of the IP address in bytes" + 1]; /**< RX buffer. */"

And change line 98 from "APP_ERROR_CHECK(nrf_drv_spi_transfer(&spi, m_tx_buf, m_length, m_rx_buf, m_length));" to:
"APP_ERROR_CHECK(nrf_drv_spi_transfer(&spi, m_tx_buf, m_length, m_rx_buf, sizeof(m_rx_buf));

Then compile, flash, and connect the nRF52DK to a terminal, like putty, etc.
The example will start an SPI transfer every 200ms, set by nrf_delay_ms() in the main loop.

RE: nRF52832 + ESP32 connection

pgonzaleztrucorp — Mon, 24 Jan 2022 10:59:33 GMT

[quote userid="13562" url="~/f/nordic-q-a/83980/nrf52832-esp32-connection/349158#349158"]The first thing you need to do is find out whether the ESP operates as an SPI master or slave. [/quote]

It's just connected to wifi and then I go to http://"WiFi.localIP()", that localIP is the one I want to send to my nordic in any way.

Let's say I configure it as slave_sender and send successfully the IP.

If I use nrfx SPI Master Example, how can I test this?

RE: nRF52832 + ESP32 connection

haakonsh — Mon, 24 Jan 2022 09:39:09 GMT

Hey pablo,

The first thing you need to do is find out whether the ESP operates as an SPI master or slave.

The second thing you need to do is study the corresponding nrfx SPI Master Example or SPI Slave Example. In both cases the received data will accessable in the event handler after an SPI transaction has completed.

Let me know when you get stuck and we'll help you further.