NDEF_MSG_PRINTOUT

[peterg0313]

I am using the nfc_writable_ndef_msg example in the SDK to write from my phone to the board using NFC. I get it working successfully however, I am also trying to add code to parse the NDEF data and print it out. However, when I run the code I have written, the COM port terminal just says NDEF Message updated and does not printout the message I have updated. Below is the function I have created and how I used it contextually within the main.  The code is all the same from nfc_writable_ndef_msg except for the one function below and it's usage in main. 

//NDEF READ AND PRINTOUT FUNCTION

void ndef_data_analyze(uint8_t * p_ndef_msg_buff, uint32_t nfc_data_len)
{
ret_code_t err_code;

uint8_t desc_buf[NDEF_FILE_SIZE];
uint32_t desc_buf_len = sizeof(desc_buf);

err_code = ndef_msg_parser(desc_buf,
&desc_buf_len,
p_ndef_msg_buff,
&nfc_data_len);
if (err_code != NRF_SUCCESS)
{
NRF_LOG_INFO("Error during parsing a NDEF message.");
}

ndef_msg_printout((nfc_ndef_msg_desc_t*) desc_buf);


}





//Main


int main(void)
{
ret_code_t err_code;

log_init();

/* Configure LED-pins as outputs */
bsp_board_init(BSP_INIT_LEDS | BSP_INIT_BUTTONS);

/* Initialize App Scheduler. */
APP_SCHED_INIT(APP_SCHED_MAX_EVENT_SIZE, APP_SCHED_QUEUE_SIZE);

/* Initialize FDS. */
err_code = ndef_file_setup();
APP_ERROR_CHECK(err_code);

/* Load NDEF message from the flash file. */
err_code = ndef_file_load(m_ndef_msg_buf, sizeof(m_ndef_msg_buf));
APP_ERROR_CHECK(err_code);

// Restore default NDEF message.
if (bsp_board_button_state_get(APP_DEFAULT_BTN))
{
uint32_t size = sizeof(m_ndef_msg_buf);
err_code = ndef_file_default_message(m_ndef_msg_buf, &size);
APP_ERROR_CHECK(err_code);
err_code = ndef_file_update(m_ndef_msg_buf, NDEF_FILE_SIZE);
APP_ERROR_CHECK(err_code);
NRF_LOG_DEBUG("Default NDEF message restored!");
}

/* Set up NFC */
err_code = nfc_t4t_setup(nfc_callback, NULL);
APP_ERROR_CHECK(err_code);

/* Run Read-Write mode for Type 4 Tag platform */
err_code = nfc_t4t_ndef_rwpayload_set(m_ndef_msg_buf, sizeof(m_ndef_msg_buf));
APP_ERROR_CHECK(err_code);

NRF_LOG_INFO("Writable NDEF message example started.");

/* Start sensing NFC field */
err_code = nfc_t4t_emulation_start();
APP_ERROR_CHECK(err_code);

//NDEF DATA ANALYZE
ndef_data_analyze(m_ndef_msg_buf, m_ndef_msg_len);

while (1)
{
app_sched_execute();

NRF_LOG_FLUSH();
__WFE();
}
}

When I run this code and update the NDEF message I get the following. I see that it is updated yet there is no printout of what I have written to the NDEF from my phone. 

I am not sure why it wont printout the message I have sent over NFC.

[peterg0313]

So I made a change to this code. I called the ndef_data_analyze function in scheduler_ndef_file_update immediately after the last NRF_LOG_print statement because I can see that is where the execution of the code is ending here. Now I get it where after the NDEF message updated! is printed that there was an error in parsing the message. That means that it is not getting to print out because for some reason there is an error in parsing the data, I will include the whole code this time but I am not sure where this error is arising. This is what I g get on the terminal. 

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/** @file
*
* @defgroup nfc_writable_ndef_msg_example_main main.c
* @{
* @ingroup nfc_writable_ndef_msg_example
* @brief The application main file of NFC writable NDEF message example.
*
*/

#include <stdint.h>
#include <stdbool.h>
#include "app_error.h"
#include "app_scheduler.h"
#include "boards.h"
#include "nfc_t4t_lib.h"
#include "nrf_log_ctrl.h"
#include "ndef_file_m.h"
#include "nfc_ndef_msg.h"
#include "nfc_ndef_msg_parser.h"
#include "nfc_ndef_msg_parser_local.h"

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

#define APP_SCHED_MAX_EVENT_SIZE 0 /**< Maximum size of scheduler events. */
#define APP_SCHED_QUEUE_SIZE 4 /**< Maximum number of events in the scheduler queue. */
#define APP_DEFAULT_BTN BSP_BOARD_BUTTON_0 /**< Button used to set default NDEF message. */

static uint8_t m_ndef_msg_buf[NDEF_FILE_SIZE]; /**< Buffer for NDEF file. */
static uint8_t m_ndef_msg_len; /**< Length of the NDEF message. */

//////NEW FUNCTION DEFINE/////////////////////////////////////

void ndef_data_analyze(uint8_t * p_ndef_msg_buff, uint32_t nfc_data_len)
{
ret_code_t err;

uint8_t desc_buf[NDEF_FILE_SIZE];
uint32_t desc_buf_len = sizeof(desc_buf);

err = ndef_msg_parser(desc_buf,
&desc_buf_len,
p_ndef_msg_buff,
&nfc_data_len);
if (err != NRF_SUCCESS)
{
NRF_LOG_INFO("Error during parsing a NDEF message.");
}

ndef_msg_printout((nfc_ndef_msg_desc_t*) desc_buf);


}

////////////////////////////////////////////////////////////////
/**
/**
* @brief Function for updating NDEF message in the flash file.
*/
static void scheduler_ndef_file_update(void * p_event_data, uint16_t event_size)
{
ret_code_t err_code;

UNUSED_PARAMETER(p_event_data);
UNUSED_PARAMETER(event_size);

// Update flash file with new NDEF message.
err_code = ndef_file_update(m_ndef_msg_buf, m_ndef_msg_len + NLEN_FIELD_SIZE);
APP_ERROR_CHECK(err_code);

NRF_LOG_INFO("NDEF message updated!");

ndef_data_analyze(m_ndef_msg_buf, m_ndef_msg_len);


}


/**
* @brief Callback function for handling NFC events.
*/
static void nfc_callback(void * context,
nfc_t4t_event_t event,
const uint8_t * data,
size_t dataLength,
uint32_t flags)
{
(void)context;

switch (event)
{
case NFC_T4T_EVENT_FIELD_ON:
bsp_board_led_on(BSP_BOARD_LED_0);
break;

case NFC_T4T_EVENT_FIELD_OFF:
bsp_board_leds_off();
break;

case NFC_T4T_EVENT_NDEF_READ:
bsp_board_led_on(BSP_BOARD_LED_3);
break;

case NFC_T4T_EVENT_NDEF_UPDATED:
if (dataLength > 0)
{
ret_code_t err_code;

bsp_board_led_on(BSP_BOARD_LED_1);

// Schedule update of NDEF message in the flash file.
m_ndef_msg_len = dataLength;
err_code = app_sched_event_put(NULL, 0, scheduler_ndef_file_update);
APP_ERROR_CHECK(err_code);
}
break;

default:
break;
}
}


/**
*@brief Function for initializing logging.
*/
static void log_init(void)
{
ret_code_t err_code = NRF_LOG_INIT(NULL);
APP_ERROR_CHECK(err_code);

NRF_LOG_DEFAULT_BACKENDS_INIT();
}


//@brief Function for application main entry.

//
int main(void)
{
ret_code_t err_code;

log_init();

/* Configure LED-pins as outputs */
bsp_board_init(BSP_INIT_LEDS | BSP_INIT_BUTTONS);

/* Initialize App Scheduler. */
APP_SCHED_INIT(APP_SCHED_MAX_EVENT_SIZE, APP_SCHED_QUEUE_SIZE);

/* Initialize FDS. */
err_code = ndef_file_setup();
APP_ERROR_CHECK(err_code);

/* Load NDEF message from the flash file. */
err_code = ndef_file_load(m_ndef_msg_buf, sizeof(m_ndef_msg_buf));
APP_ERROR_CHECK(err_code);

// Restore default NDEF message.
if (bsp_board_button_state_get(APP_DEFAULT_BTN))
{
uint32_t size = sizeof(m_ndef_msg_buf);
err_code = ndef_file_default_message(m_ndef_msg_buf, &size);
APP_ERROR_CHECK(err_code);
err_code = ndef_file_update(m_ndef_msg_buf, NDEF_FILE_SIZE);
APP_ERROR_CHECK(err_code);
NRF_LOG_DEBUG("Default NDEF message restored!");
}

/* Set up NFC */
err_code = nfc_t4t_setup(nfc_callback, NULL);
APP_ERROR_CHECK(err_code);

/* Run Read-Write mode for Type 4 Tag platform */
err_code = nfc_t4t_ndef_rwpayload_set(m_ndef_msg_buf, sizeof(m_ndef_msg_buf));
APP_ERROR_CHECK(err_code);

NRF_LOG_INFO("Writable NDEF message example started.");

/* Start sensing NFC field */
err_code = nfc_t4t_emulation_start();
APP_ERROR_CHECK(err_code);

//NDEF DATA ANALYZE
//ndef_data_analyze(m_ndef_msg_buf, m_ndef_msg_len);

while (1)
{
app_sched_execute();

NRF_LOG_FLUSH();
__WFE();
}
}


/** @} */

[Joakim Jakobsen]

Hi.

I'll forward this to our NFC developers, and get back to you with a comment from them.

For future reference:
When you post code snippets here, it's a lot easier for us to read if you use the feature "Insert -> Code" or upload the source code in a file.

Br,
Joakim

[Joakim Jakobsen]

Hi again. 

A comment from our developers: 

"Parse the buffer which contains NDEF message without NLEN field. Usually NLEN field is two bytes length and occupies first bytes of the NDEF message buffer."

Please give this a try at let me know if this doesn't fix the issue. 

Br, 
Joakim