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fix LF emulation; make continuous sending ID; increase field sensing period

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This commit is contained in:
Dmytro Klishchevskyi
2024-08-05 21:30:55 +02:00
parent c771ae937b
commit b655c7351a
2 changed files with 12 additions and 3 deletions
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firmware/application/src/rfid/nfctag/lf/lf_tag_em.c
+10 -2
View File
@@ -201,7 +201,8 @@ uint64_t em410x_id_to_memory64(uint8_t id[5]) {
*/
bool lf_is_field_exists(void) {
nrf_drv_lpcomp_enable();
bsp_delay_us(20); // Display for a period of time and sampling to avoid misjudgment
// With 20ms of delay CU was not able to detect the field of my reader after waking up.
bsp_delay_us(30); // Display for a period of time and sampling to avoid misjudgment
nrf_lpcomp_task_trigger(NRF_LPCOMP_TASK_SAMPLE); //Trigger a sampling
return nrf_lpcomp_result_get() == 1; //Determine the sampling results of the LF field status
}
@@ -261,7 +262,14 @@ void timer_ce_handler(nrf_timer_event_t event_type, void *p_context) {
if (m_is_send_first_edge == true) { // The first edge of the next sends next time
if (++m_bit_send_position >= LF_125KHZ_EM410X_BIT_SIZE) {
m_bit_send_position = 0; // The broadcast is successful once, and the BIT position is zero
if (++m_send_id_count >= LF_125KHZ_BROADCAST_MAX) {
/* The main part of the idea. The original EM4100 tag continuously sends it's ID.
* The root problem, in my point of view, was that CU started to "feel" the field too far to be able to modulate it deep enough,
* and 3 times (LF_125KHZ_BROADCAST_MAX) of repeating takes only about 100ms, CU is still not close enough to the reader.
* That is why the emulation worked only if the CU moved past the reader quickly (fly by).*/
if(!lf_is_field_exists()){
m_send_id_count++;
}
if (m_send_id_count >= LF_125KHZ_BROADCAST_MAX) {
m_send_id_count = 0; //The number of broadcasts reaches the upper limit, re -identifies the status of the field and re -statistically count the number of broadcast times
}
}
firmware/application/src/rfid/nfctag/lf/lf_tag_em.h
+2 -1
View File
@@ -11,7 +11,8 @@
* The definition of the packaging tool macro only needs to be modulated 0 and 1
*/
#define LF_125KHZ_EM410X_BIT_SIZE 64
#define LF_125KHZ_BROADCAST_MAX 3 // 32.768ms once, about 31 times in one second
// Have decided to increase the period of field sensing in this way
#define LF_125KHZ_BROADCAST_MAX 10 // 32.768ms once, about 31 times in one second
#define LF_125KHZ_EM410X_BIT_CLOCK 256
#define LF_EM410X_TAG_ID_SIZE 5