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LF EM: make sure to sample the field only during the last no-mod half bit of a series of ID broadcasts

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This commit is contained in:
Philippe Teuwen
2023-07-18 17:52:56 +02:00
parent 6ea244745b
commit aac1315087
1 changed files with 18 additions and 7 deletions
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firmware/application/src/rfid/nfctag/lf/lf_tag_em.c
+18 -7
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@@ -125,6 +125,7 @@ uint64_t em410x_id_to_memory64(uint8_t id[5]) {
}
void timer_ce_handler(nrf_timer_event_t event_type, void* p_context) {
bool mod;
switch (event_type) {
// 因为我们配置的是使用CC通道2，所以事件回调
// 函数中判断NRF_TIMER_EVENT_COMPARE0事件
@@ -133,29 +134,30 @@ void timer_ce_handler(nrf_timer_event_t event_type, void* p_context) {
if (GETBIT(m_id_bit_data, m_bit_send_position)) {
// 发送 1 的第一个沿
ANT_TO_MOD();
mod = true;
} else {
// 发送 0 的第一个沿
ANT_NO_MOD();
mod = false;
}
m_is_send_first_edge = false; // 下次发送第二个沿
} else {
if (GETBIT(m_id_bit_data, m_bit_send_position)) {
// 发送 1 的第二个沿
ANT_NO_MOD();
mod = false;
} else {
// 发送 0 的第二个沿
ANT_TO_MOD();
mod = true;
}
m_is_send_first_edge = true; // 下次发送第一个沿
if (++m_bit_send_position >= LF_125KHZ_EM410X_BIT_SIZE) {
m_bit_send_position = 0; // 广播一次成功，bit位置归零
++m_send_id_count; // 统计广播次数
}
}
// 如果广播次数超过上限次数，则重新比较场状态，根据新的场状态选择是否继续模拟标签
if (m_send_id_count >= LF_125KHZ_BORADCAST_MAX) {
m_send_id_count = 0; // 广播次数达到上限，重新识别场状态并且重新统计广播次数
// measure field only during no-mod half of last bit of last broadcast
if ((! mod) &&
(m_bit_send_position + 1 >= LF_125KHZ_EM410X_BIT_SIZE) &&
(m_send_id_count + 1 >= LF_125KHZ_BORADCAST_MAX)) {
nrfx_timer_disable(&m_timer_send_id); // 关闭广播场的定时器
// 我们不需要任何的事件，仅仅需要检测一下场的状态
NRF_LPCOMP->INTENCLR = LPCOMP_INTENCLR_CROSS_Msk | LPCOMP_INTENCLR_UP_Msk | LPCOMP_INTENCLR_DOWN_Msk | LPCOMP_INTENCLR_READY_Msk;
@@ -172,6 +174,15 @@ void timer_ce_handler(nrf_timer_event_t event_type, void* p_context) {
NRF_LOG_INFO("LF FIELD LOST");
}
}
if (m_is_send_first_edge == true) { // 下次发送第一个沿
if (++m_bit_send_position >= LF_125KHZ_EM410X_BIT_SIZE) {
m_bit_send_position = 0; // 广播一次成功，bit位置归零
if (++m_send_id_count >= LF_125KHZ_BORADCAST_MAX) {
m_send_id_count = 0; // 广播次数达到上限，重新识别场状态并且重新统计广播次数
}
}
}
break;
}
default: {