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rework NfcA and simplify a bit

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digital_sequence_bake added for testing purpose
This commit is contained in:
g3gg0
2022-11-22 00:34:09 +01:00
parent 60b2c5cf67
commit eb98c7b246
3 changed files with 99 additions and 36 deletions
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94
lib/nfc/protocols/nfca.c
View File

@@ -14,6 +14,13 @@
#define NFCA_SIGNAL_MAX_EDGES (1350)
#define SEQ_SOF 0
#define SEQ_BIT0 1
#define SEQ_BIT1 2
#define SEQ_EOF 3
#define SEQ_IDLE 4
typedef struct {
uint8_t cmd;
uint8_t param;
@@ -62,49 +69,63 @@ bool nfca_emulation_handler(
return sleep;
}
static void nfca_add_bit(DigitalSignal* signal, bool bit) {
signal->start_level = bit;
signal->edge_cnt = 0;
if(bit) {
for(size_t i = 0; i < 7; i++) {
signal->edge_timings[signal->edge_cnt++] = DIGITAL_SIGNAL_PS(T_SUB_PHASE);
}
signal->edge_timings[signal->edge_cnt++] = DIGITAL_SIGNAL_PS(T_SUB_PHASE * 9);
} else {
signal->edge_timings[signal->edge_cnt++] = DIGITAL_SIGNAL_PS(T_SUB_PHASE * 8);
for(size_t i = 0; i < 8; i++) {
signal->edge_timings[signal->edge_cnt++] = DIGITAL_SIGNAL_PS(T_SUB_PHASE);
}
}
}
static void nfca_add_byte(NfcaSignal* nfca_signal, uint8_t byte, bool parity) {
for(uint8_t i = 0; i < 8; i++) {
if(byte & (1 << i)) {
digital_sequence_add(nfca_signal->tx_signal, 1);
digital_sequence_add(nfca_signal->tx_signal, SEQ_BIT1);
} else {
digital_sequence_add(nfca_signal->tx_signal, 0);
digital_sequence_add(nfca_signal->tx_signal, SEQ_BIT0);
}
}
if(parity) {
digital_sequence_add(nfca_signal->tx_signal, 1);
digital_sequence_add(nfca_signal->tx_signal, SEQ_BIT1);
} else {
digital_sequence_add(nfca_signal->tx_signal, 0);
digital_sequence_add(nfca_signal->tx_signal, SEQ_BIT0);
}
}
static void nfca_add_modulation(DigitalSignal* signal, size_t phases) {
for(size_t i = 0; i < phases; i++) {
signal->edge_timings[signal->edge_cnt++] = DIGITAL_SIGNAL_PS(T_SUB_PHASE);
}
}
static void nfca_add_silence(DigitalSignal* signal, size_t phases) {
signal->edge_timings[signal->edge_cnt++] = DIGITAL_SIGNAL_PS(phases * T_SUB_PHASE);
}
NfcaSignal* nfca_signal_alloc() {
NfcaSignal* nfca_signal = malloc(sizeof(NfcaSignal));
nfca_signal->one = digital_signal_alloc(10);
nfca_signal->zero = digital_signal_alloc(10);
nfca_add_bit(nfca_signal->one, true);
nfca_add_bit(nfca_signal->zero, false);
/* ISO14443-2 defines 3 sequences for type A communication */
nfca_signal->seq_d = digital_signal_alloc(10);
nfca_signal->seq_e = digital_signal_alloc(10);
nfca_signal->seq_f = digital_signal_alloc(10);
/* start all sequences without load. polarity is not defined by standard,
so pick the polarity the best for us */
nfca_signal->seq_d->start_level = false;
nfca_signal->seq_e->start_level = false;
nfca_signal->seq_f->start_level = false;
/* SEQ D has the first half modulated, used as SOF */
nfca_add_modulation(nfca_signal->seq_d, 4);
nfca_add_silence(nfca_signal->seq_d, 4);
/* SEQ E has the second half modulated */
nfca_add_silence(nfca_signal->seq_e, 4);
nfca_add_modulation(nfca_signal->seq_e, 4);
/* SEQ F is just no modulation, used as EOF */
nfca_add_silence(nfca_signal->seq_f, 8);
nfca_signal->tx_signal = digital_sequence_alloc(NFCA_SIGNAL_MAX_EDGES);
digital_sequence_set_signal(nfca_signal->tx_signal, 0, nfca_signal->zero);
digital_sequence_set_signal(nfca_signal->tx_signal, 1, nfca_signal->one);
digital_sequence_set_signal(nfca_signal->tx_signal, SEQ_SOF, nfca_signal->seq_d);
digital_sequence_set_signal(nfca_signal->tx_signal, SEQ_BIT0, nfca_signal->seq_e);
digital_sequence_set_signal(nfca_signal->tx_signal, SEQ_BIT1, nfca_signal->seq_d);
digital_sequence_set_signal(nfca_signal->tx_signal, SEQ_EOF, nfca_signal->seq_f);
digital_sequence_set_signal(nfca_signal->tx_signal, SEQ_IDLE, nfca_signal->seq_f);
return nfca_signal;
}
@@ -112,8 +133,9 @@ NfcaSignal* nfca_signal_alloc() {
void nfca_signal_free(NfcaSignal* nfca_signal) {
furi_assert(nfca_signal);
digital_signal_free(nfca_signal->one);
digital_signal_free(nfca_signal->zero);
digital_signal_free(nfca_signal->seq_d);
digital_signal_free(nfca_signal->seq_e);
digital_signal_free(nfca_signal->seq_f);
digital_sequence_free(nfca_signal->tx_signal);
free(nfca_signal);
}
@@ -125,14 +147,18 @@ void nfca_signal_encode(NfcaSignal* nfca_signal, uint8_t* data, uint16_t bits, u
digital_sequence_clear(nfca_signal->tx_signal);
digital_sequence_add(nfca_signal->tx_signal, 1);
/* add some idle bit times before SOF */
for(int pos = 0; pos < 4; pos++) {
digital_sequence_add(nfca_signal->tx_signal, SEQ_IDLE);
}
digital_sequence_add(nfca_signal->tx_signal, SEQ_SOF);
if(bits < 8) {
for(size_t i = 0; i < bits; i++) {
if(FURI_BIT(data[0], i)) {
digital_sequence_add(nfca_signal->tx_signal, 1);
digital_sequence_add(nfca_signal->tx_signal, SEQ_BIT1);
} else {
digital_sequence_add(nfca_signal->tx_signal, 0);
digital_sequence_add(nfca_signal->tx_signal, SEQ_BIT0);
}
}
} else {
@@ -140,4 +166,6 @@ void nfca_signal_encode(NfcaSignal* nfca_signal, uint8_t* data, uint16_t bits, u
nfca_add_byte(nfca_signal, data[i], parity[i / 8] & (1 << (7 - (i & 0x07))));
}
}
digital_sequence_add(nfca_signal->tx_signal, SEQ_EOF);
}

5
lib/nfc/protocols/nfca.h
View File

@@ -6,8 +6,9 @@
#include <lib/digital_signal/digital_signal.h>
typedef struct {
DigitalSignal* one;
DigitalSignal* zero;
DigitalSignal* seq_d; /* sequence D, modulation with subcarrier during first half */
DigitalSignal* seq_e; /* sequence E, modulation with subcarrier during second half */
DigitalSignal* seq_f; /* sequence F, no modulation at all */
DigitalSequence* tx_signal;
} NfcaSignal;