Hello,
I am trying to develop an application where I can turn on/off the NFC T4T tag emulation using interrupt-driven buttons.
However, after the first read of the NFC tag, only NFC callback events can be run, while blocking any other code to run(Including button interrupts, and logging).
I couldn't solve the issue by myself, and I would appreciate it if you can help.
I attached my code below.
/*
* Copyright (c) 2018 Nordic Semiconductor ASA
*
* SPDX-License-Identifier: LicenseRef-Nordic-5-Clause
*/
#include <zephyr/kernel.h>
#include <zephyr/sys/reboot.h>
#include <nfc_t4t_lib.h>
#include <nfc/t4t/ndef_file.h>
#include <nfc/ndef/msg.h>
#include <nfc/ndef/text_rec.h>
#include <dk_buttons_and_leds.h>
#define MAX_REC_COUNT 1
#define NDEF_MSG_BUF_SIZE 128
#define NFC_FIELD_LED DK_LED1
#define NFC_SW_BUTTON DK_BTN1_MSK
int nfc_state;
/* Text message in English with its language code. */
static const uint8_t en_payload[] = {
'H', 'e', 'l', 'l', 'o', ' ', 'W', 'o', 'r', 'l', 'd', '!'
};
static const uint8_t en_code[] = {'e', 'n'};
/* Buffer used to hold an NFC NDEF message. */
static uint8_t ndef_msg_buf[NDEF_MSG_BUF_SIZE];
static void nfc_callback(void *context,
nfc_t4t_event_t event,
const uint8_t *data,
size_t data_length)
{
ARG_UNUSED(context);
ARG_UNUSED(data);
ARG_UNUSED(data_length);
switch (event) {
case NFC_T4T_EVENT_FIELD_ON:
dk_set_led_on(NFC_FIELD_LED);
break;
case NFC_T4T_EVENT_FIELD_OFF:
dk_set_led_off(NFC_FIELD_LED);
break;
default:
break;
}
}
/**
* @brief Function for encoding the NDEF text message.
*/
static int welcome_msg_encode(uint8_t *buffer, uint32_t *len)
{
int err;
/* Create NFC NDEF text record description in English */
NFC_NDEF_TEXT_RECORD_DESC_DEF(nfc_en_text_rec,
UTF_8,
en_code,
sizeof(en_code),
en_payload,
sizeof(en_payload));
/* Create NFC NDEF message description, capacity - MAX_REC_COUNT
* records
*/
NFC_NDEF_MSG_DEF(nfc_text_msg, MAX_REC_COUNT);
/* Add text records to NDEF text message */
err = nfc_ndef_msg_record_add(&NFC_NDEF_MSG(nfc_text_msg),
&NFC_NDEF_TEXT_RECORD_DESC(nfc_en_text_rec));
if (err < 0) {
printk("Cannot add first record!\n");
return err;
}
err = nfc_ndef_msg_encode(&NFC_NDEF_MSG(nfc_text_msg),
buffer,
len);
if (err < 0) {
printk("Cannot encode message!\n");
}
return err;
}
static void button_changed(uint32_t button_state, uint32_t has_changed)
{
int err;
if (has_changed & NFC_SW_BUTTON) {
uint32_t user_button_state = button_state & NFC_SW_BUTTON;
if (user_button_state == 1) {
if (nfc_state == 1) {
err = nfc_t4t_emulation_stop();
if (err) {
printk("Cannot stop emulation\n");
} else {
printk("Emulation stopped\n");
nfc_state = 0;
}
} else {
err = nfc_t4t_emulation_start();
if (err) {
printk("Cannot start emulation\n");
} else {
printk("Emulation started\n");
nfc_state = 1;
}
}
}
}
}
int main(void)
{
uint32_t len = nfc_t4t_ndef_file_msg_size_get(sizeof(ndef_msg_buf));
printk("Starting NFC Text Record example\n");
/* Configure LED-pins as outputs */
if (dk_leds_init() < 0) {
printk("Cannot init LEDs!\n");
goto fail;
}
if (dk_buttons_init(button_changed) < 0) {
printk("Cannot init buttons!\n");
goto fail;
}
/* Set up NFC */
if (nfc_t4t_setup(nfc_callback, NULL) < 0) {
printk("Cannot setup NFC T2T library!\n");
goto fail;
}
/* Encode welcome message */
if (welcome_msg_encode(nfc_t4t_ndef_file_msg_get(ndef_msg_buf), &len) < 0) {
printk("Cannot encode message!\n");
goto fail;
}
nfc_t4t_ndef_file_encode(ndef_msg_buf, &len);
/* Set created message as the NFC payload */
if (nfc_t4t_ndef_rwpayload_set(ndef_msg_buf, sizeof(ndef_msg_buf)) < 0) {
printk("Cannot set payload!\n");
goto fail;
}
/* Start sensing NFC field */
if (nfc_t4t_emulation_start() < 0) {
printk("Cannot start emulation!\n");
goto fail;
}
nfc_state = 1;
printk("NFC configuration done\n");
return 0;
fail:
#if CONFIG_REBOOT
sys_reboot(SYS_REBOOT_COLD);
#endif /* CONFIG_REBOOT */
return -EIO;
}
