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- used WaitUS() instead of own function for reading operations

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- used GetTicks() instead of using direct timer TC0
=> standalone mode functions can be simplified significantly
This commit is contained in:
tharexde 2021-01-27 01:10:57 +01:00
commit 1c3d3b350a
1 changed files with 23 additions and 91 deletions
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114
armsrc/em4x50.c
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@ -28,11 +28,12 @@
#define T0 192
#endif
// the following terms are used (for carrier frequency of 125 kHz):
// conversions (carrier frequency 125 kHz):
// 1 us = 1.5 ticks
// 1 cycle = 1 period = 8 us = 12 ticks
// 1 bit = 64 cycles = 768 ticks = 512 us
// 1 bit = 64 cycles = 768 ticks = 512 us (for Opt64)
#define CYCLES2TICKS 12
#define CYCLES2MUSEC 8
// given in cycles/periods
#define EM4X50_T_TAG_QUARTER_PERIOD 16
@ -46,8 +47,8 @@
#define EM4X50_T_TAG_WAITING_FOR_SIGNAL 75
#define EM4X50_T_WAITING_FOR_DBLLIW 1550
#define EM4X50_T_WAITING_FOR_ACK 4
#define EM4X50_TAG_TOLERANCE 8
#define EM4X50_ZERO_DETECTION 3
#define EM4X50_T_TOLERANCE 8
#define EM4X50_T_ZERO_DETECTION 3
// timeout values (empirical) for simulation mode (may vary with regard to reader)
#define EM4X50_T_SIMULATION_TIMEOUT_READ 600
@ -72,17 +73,6 @@ bool gLogin = false;
// to be able to identfiy it
bool gWritePasswordProcess = false;
// do nothing for <period> using timer0
static void wait_timer(uint32_t period) {
int timeout = period;
uint32_t tval = GetTicks();
//AT91C_BASE_TC0->TC_CCR = AT91C_TC_SWTRG;
//while (AT91C_BASE_TC0->TC_CV < period);
while ((timeout--) && (GetTicks() - tval < period));
}
// extract and check parities
// return result of parity check and extracted plain data
static bool extract_parities(uint64_t word, uint32_t *data) {
@ -142,7 +132,6 @@ void em4x50_setup_read(void) {
StartTicks();
// 50ms for the resonant antenna to settle.
//SpinDelay(50);
WaitMS(50);
// Now set up the SSC to get the ADC samples that are now streaming at us.
@ -161,27 +150,6 @@ void em4x50_setup_read(void) {
// Disable modulation at default, which means enable the field
LOW(GPIO_SSC_DOUT);
/*
// Enable Peripheral Clock for
// TIMER_CLOCK0, used to measure exact timing before answering
AT91C_BASE_PMC->PMC_PCER |= (1 << AT91C_ID_TC0);// | (1 << AT91C_ID_TC1);
AT91C_BASE_PIOA->PIO_BSR = GPIO_SSC_FRAME;
// Disable timer during configuration
AT91C_BASE_TC0->TC_CCR = AT91C_TC_CLKDIS;
// TC0: Capture mode, default timer source = MCK/2 (TIMER_CLOCK1), no triggers
AT91C_BASE_TC0->TC_CMR = AT91C_TC_CLKS_TIMER_DIV1_CLOCK;
// TC1: Capture mode, default timer source = MCK/2 (TIMER_CLOCK1), no triggers
// Enable and reset counters
AT91C_BASE_TC0->TC_CCR = AT91C_TC_CLKEN | AT91C_TC_SWTRG;
// synchronized startup procedure
while (AT91C_BASE_TC0->TC_CV > 0) {}; // wait until TC1 returned to zero
*/
// Watchdog hit
WDT_HIT();
}
@ -196,13 +164,6 @@ void em4x50_setup_sim(void) {
AT91C_BASE_PIOA->PIO_ODR = GPIO_SSC_CLK;
StartTicks();
/*
AT91C_BASE_PMC->PMC_PCER |= (1 << AT91C_ID_TC0);
AT91C_BASE_PIOA->PIO_BSR = GPIO_SSC_FRAME;
AT91C_BASE_TC0->TC_CCR = AT91C_TC_CLKDIS;
AT91C_BASE_TC0->TC_CMR = AT91C_TC_CLKS_TIMER_DIV1_CLOCK;
AT91C_BASE_TC0->TC_CCR = AT91C_TC_CLKEN | AT91C_TC_SWTRG;
*/
// Watchdog hit
WDT_HIT();
@ -231,8 +192,7 @@ bool get_signalproperties(void) {
if (BUTTON_PRESS()) return false;
// about 2 samples per bit period
//wait_timer(T0 * EM4X50_T_TAG_HALF_PERIOD);
wait_timer(12 * EM4X50_T_TAG_HALF_PERIOD);
WaitUS(EM4X50_T_TAG_HALF_PERIOD * CYCLES2MUSEC);
// ignore first samples
if ((i > SIGNAL_IGNORE_FIRST_SAMPLES) && (AT91C_BASE_SSC->SSC_RHR > noise)) {
@ -250,8 +210,6 @@ bool get_signalproperties(void) {
// 3 single "full periods" to eliminate the influence of a listen window
for (int i = 0; i < no_periods; i++) {
//AT91C_BASE_TC0->TC_CCR = AT91C_TC_SWTRG;
//while (AT91C_BASE_TC0->TC_CV < T0 * 3 * EM4X50_T_TAG_FULL_PERIOD) {
tval = GetTicks();
while (GetTicks() - tval < 12 * 3 * EM4X50_T_TAG_FULL_PERIOD) {
@ -284,14 +242,12 @@ bool get_signalproperties(void) {
static bool invalid_bit(void) {
// get sample at 3/4 of bit period
//wait_timer(T0 * EM4X50_T_TAG_THREE_QUARTER_PERIOD);
wait_timer(12 * EM4X50_T_TAG_THREE_QUARTER_PERIOD);
WaitUS(EM4X50_T_TAG_THREE_QUARTER_PERIOD * CYCLES2MUSEC);
uint8_t sample = (uint8_t)AT91C_BASE_SSC->SSC_RHR;
// wait until end of bit period
//wait_timer(T0 * EM4X50_T_TAG_QUARTER_PERIOD);
wait_timer(12 * EM4X50_T_TAG_QUARTER_PERIOD);
WaitUS(EM4X50_T_TAG_QUARTER_PERIOD * CYCLES2MUSEC);
// bit in "undefined" state?
if (sample <= gHigh && sample >= gLow)
@ -314,7 +270,6 @@ static uint32_t get_pulse_length(void) {
if (timeout == 0)
return 0;
//AT91C_BASE_TC0->TC_CCR = AT91C_TC_SWTRG;
tval = GetTicks();
timeout = (T0 * 3 * EM4X50_T_TAG_FULL_PERIOD);
@ -331,23 +286,20 @@ static uint32_t get_pulse_length(void) {
if (timeout == 0)
return 0;
//return (uint32_t)AT91C_BASE_TC0->TC_CV;
return GetTicks() - tval;
}
// check if pulse length <pl> corresponds to given length <length>
static bool check_pulse_length(uint32_t pl, int length) {
//return ((pl >= T0 * (length - EM4X50_TAG_TOLERANCE)) && (pl <= T0 * (length + EM4X50_TAG_TOLERANCE)));
return ((pl >= 12 * (length - EM4X50_TAG_TOLERANCE)) && (pl <= 12 * (length + EM4X50_TAG_TOLERANCE)));
return ((pl >= (length - EM4X50_T_TOLERANCE) * CYCLES2TICKS) &&
(pl <= (length + EM4X50_T_TOLERANCE) * CYCLES2TICKS));
}
// send single bit according to EM4x50 application note and datasheet
static void em4x50_reader_send_bit(int bit) {
int timeout = 500;
// reset clock for the next bit
//AT91C_BASE_TC0->TC_CCR = AT91C_TC_SWTRG;
uint32_t tval = GetTicks();
if (bit == 0) {
@ -356,34 +308,22 @@ static void em4x50_reader_send_bit(int bit) {
// period (Opt64)
LOW(GPIO_SSC_DOUT);
//while (AT91C_BASE_TC0->TC_CV < T0 * 7);
while ((timeout--) && (GetTicks() - tval < 12 * 7));
if (timeout <= 0)
return;
timeout = 500;
while (GetTicks() - tval < 7 * CYCLES2TICKS);
// enable modulation (drop the field) for remaining first
// half of bit period
HIGH(GPIO_SSC_DOUT);
//while (AT91C_BASE_TC0->TC_CV < T0 * EM4X50_T_TAG_HALF_PERIOD);
while ((timeout--) && (GetTicks() - tval < 12 * EM4X50_T_TAG_HALF_PERIOD));
if (timeout <= 0)
return;
timeout = 500;
while (GetTicks() - tval < EM4X50_T_TAG_HALF_PERIOD * CYCLES2TICKS);
// disable modulation for second half of bit period
LOW(GPIO_SSC_DOUT);
//while (AT91C_BASE_TC0->TC_CV < T0 * EM4X50_T_TAG_FULL_PERIOD);
while ((timeout--) && (GetTicks() - tval < 12 * EM4X50_T_TAG_FULL_PERIOD));
if (timeout <= 0)
return;
timeout = 500;
while (GetTicks() - tval < EM4X50_T_TAG_FULL_PERIOD * CYCLES2TICKS);
} else {
// bit = "1" means disable modulation for full bit period
LOW(GPIO_SSC_DOUT);
//while (AT91C_BASE_TC0->TC_CV < T0 * EM4X50_T_TAG_FULL_PERIOD);
while ((timeout--) && (GetTicks() - tval < 12 * EM4X50_T_TAG_FULL_PERIOD));
while (GetTicks() - tval < EM4X50_T_TAG_FULL_PERIOD * CYCLES2TICKS);
}
}
@ -483,8 +423,7 @@ static int find_double_listen_window(bool bcommand) {
// second window follows - sync on this to issue a command
// skip the next bit...
//wait_timer(T0 * EM4X50_T_TAG_FULL_PERIOD);
wait_timer(12 * EM4X50_T_TAG_FULL_PERIOD);
WaitUS(EM4X50_T_TAG_FULL_PERIOD * CYCLES2MUSEC);
// ...and check if the following bit does make sense
// (if not it is the correct position within the second
@ -562,8 +501,7 @@ static bool check_ack(bool bliw) {
// wait for 2 bits (remaining "bit" of ACK signal + first
// "bit" of listen window)
//wait_timer(T0 * 2 * EM4X50_T_TAG_FULL_PERIOD);
wait_timer(12 * 2 * EM4X50_T_TAG_FULL_PERIOD);
WaitUS(2 * EM4X50_T_TAG_FULL_PERIOD * CYCLES2MUSEC);
// check for listen window (if first bit cannot be interpreted
// as a valid bit it must belong to a listen window)
@ -694,8 +632,7 @@ static bool login(uint32_t password) {
// send password
em4x50_reader_send_word(password);
//wait_timer(T0 * EM4X50_T_TAG_TPP);
wait_timer(12 * EM4X50_T_TAG_TPP);
WaitUS(EM4X50_T_TAG_TPP * CYCLES2MUSEC);
// check if ACK is returned
if (check_ack(false))
@ -1000,8 +937,7 @@ static int write(uint32_t word, uint32_t addresses) {
} else {
// wait for T0 * EM4X50_T_TAG_TWA (write access time)
//wait_timer(T0 * EM4X50_T_TAG_TWA);
wait_timer(12 * EM4X50_T_TAG_TWA);
WaitUS(EM4X50_T_TAG_TWA * CYCLES2MUSEC);
// look for ACK sequence
if (check_ack(false)) {
@ -1009,8 +945,7 @@ static int write(uint32_t word, uint32_t addresses) {
// now EM4x50 needs T0 * EM4X50_T_TAG_TWEE (EEPROM write time = 3.2ms = 50 * 64 periods)
// for saving data and should return with ACK
for (int i = 0; i < 50; i++) {
//wait_timer(T0 * EM4X50_T_TAG_FULL_PERIOD);
wait_timer(12 * EM4X50_T_TAG_FULL_PERIOD);
WaitUS(EM4X50_T_TAG_FULL_PERIOD * CYCLES2MUSEC);
}
if (check_ack(false))
@ -1041,8 +976,7 @@ static int write_password(uint32_t password, uint32_t new_password) {
} else {
// wait for T0 * EM4x50_T_TAG_TPP (processing pause time)
//wait_timer(T0 * EM4X50_T_TAG_TPP);
wait_timer(12 * EM4X50_T_TAG_TPP);
WaitUS(EM4X50_T_TAG_TPP * CYCLES2MUSEC);
// look for ACK sequence and send rm request
// during following listen window
@ -1052,16 +986,14 @@ static int write_password(uint32_t password, uint32_t new_password) {
em4x50_reader_send_word(new_password);
// wait for T0 * EM4X50_T_TAG_TWA (write access time)
//wait_timer(T0 * EM4X50_T_TAG_TWA);
wait_timer(12 * EM4X50_T_TAG_TWA);
WaitUS(EM4X50_T_TAG_TWA * CYCLES2MUSEC);
if (check_ack(false)) {
// now EM4x50 needs T0 * EM4X50_T_TAG_TWEE (EEPROM write time = 3.2ms = 50 * 64 periods)
// for saving data and should return with ACK
for (int i = 0; i < 50; i++) {
//wait_timer(T0 * EM4X50_T_TAG_FULL_PERIOD);
wait_timer(12 * EM4X50_T_TAG_FULL_PERIOD);
WaitUS(EM4X50_T_TAG_FULL_PERIOD * CYCLES2MUSEC);
}
if (check_ack(false))
@ -1276,7 +1208,7 @@ static int em4x50_sim_read_bit(void) {
while (AT91C_BASE_PIOA->PIO_PDSR & GPIO_SSC_CLK) {
// check if current cycle takes longer than "usual""
if (GetTicks() - tval > EM4X50_ZERO_DETECTION * CYCLES2TICKS) {
if (GetTicks() - tval > EM4X50_T_ZERO_DETECTION * CYCLES2TICKS) {
// gap detected; wait until reader field is switched on again
while ((timeout--) && (AT91C_BASE_PIOA->PIO_PDSR & GPIO_SSC_CLK));