void read_PSK1_HW_clock(unsigned int period, unsigned int ticks, BYTE *data, unsigned int bits, unsigned int timeout_us, unsigned int min_pulse_us)
{
// point globals at data for ISR
EMU_Data= data;
HW_Bits= bits;
PSK_Min_Pulse= min_pulse_us;
PSK_Read_Error= FALSE;
memset(EMU_Data, '\0', bits);
// stop USB interfering
USBMaskInterrupts();
// start clock if not already running
if(!mGetLED_Clock() == mLED_ON)
{
InitHWReaderClock(OC_TOGGLE_PULSE, period / 2L, period, RWD_STATE_ACTIVE);
// give reader time to wake up and settle
Delay_us((RFIDlerConfig.FrameClock * RFIDlerConfig.RWD_Wake_Period) / 100);
}
// reset timer for timeout
GetTimer_us(RESET);
// align ourselves to reader's bit period by finding start of a pulse
while(READER_DATA)
if(timeout_us)
if (GetTimer_us(NO_RESET) > timeout_us)
return;
while(!READER_DATA)
if(timeout_us)
if (GetTimer_us(NO_RESET) > timeout_us)
return;
// reset timer for external timeouts
GetTimer_us(RESET);
// start ISR to read PSK data
InitHWReaderISR(CONVERT_TO_TICKS(period) * ticks - 1L, TRUE);
}
// h/w clock reader - initialise data pointers for ISR and start timers
// timer2 creates clock output for external reader
// timer4 reads data bit values
// period_us == clock for reader
// ticks == clock periods per bit
// bits == number of bits to read
// oneshot must be set if we are reading data in response to RWD, so no repeating stream
BOOL read_ASK_HW_clock(unsigned int period, unsigned int ticks, BYTE *data, unsigned int bits, unsigned int timeout_us, BOOL oneshot)
{
unsigned long dwell, time;
BYTE count;
Manchester_Error= FALSE;
// if we're manchester or bi-phase encoding, we want to clock twice as fast so we can read both halves of the bit
if(RFIDlerConfig.Manchester || RFIDlerConfig.BiPhase)
{
ticks /= 2;
HW_Bits= (unsigned long) bits * 2;
}
else
HW_Bits= (unsigned long) bits;
// point globals at data for ISR
EMU_Data= data;
memset(EMU_Data, '\0', bits);
// stop USB interfering
USBMaskInterrupts();
// start clock if not already running
if(!mGetLED_Clock() == mLED_ON)
{
InitHWReaderClock(OC_TOGGLE_PULSE, period / 2L, period, RWD_STATE_ACTIVE);
// give reader time to wake up and settle
Delay_us((RFIDlerConfig.FrameClock * RFIDlerConfig.RWD_Wake_Period) / 100);
}
// align ourselves to reader's bit period by waiting until the end of a pulse
GetTimer_us(RESET);
count= READER_DATA;
while(count == READER_DATA)
if(GetTimer_us(NO_RESET) > timeout_us)
return FALSE;
// convert to ticks
period= CONVERT_TO_TICKS(period);
// biphase cannot auto-align when it detects a half-bit error, so we must align
// on a full bit before we start
if(!oneshot && RFIDlerConfig.BiPhase)
{
dwell= period * ticks * 2;
count= 0;
while((time= get_reader_gap(timeout_us)))
{
if(!time || count == 255)
return;
else
if(approx(time, dwell, 10))
break;
++count;
}
}
// wait for half the bit period so we sample mid-tick, not just as bit is toggling
dwell= ((period * ticks) / 2L);
GetTimer_ticks(RESET);
//DEBUG_PIN_2= HIGH;
while(GetTimer_ticks(NO_RESET) < dwell)
;
// reset timer for external timeouts
GetTimer_us(RESET);
//DEBUG_PIN_2= LOW;
// re-start reader ISR to read this bit if required
InitHWReaderISR(period * ticks - 1L, TRUE);
return TRUE;
}
BOOL read_FSK_HW_clock(unsigned int period, unsigned int ticks, BYTE *data, unsigned int bits, unsigned int timeout_us)
{
unsigned int gaplength;
// point globals at data for ISR
EMU_Data= data;
HW_Bits= bits;
memset(EMU_Data, '\0', bits);
// stop USB interfering
USBMaskInterrupts();
// start clock if not already running
if(!mGetLED_Clock() == mLED_ON)
{
InitHWReaderClock(OC_TOGGLE_PULSE, period / 2L, period, RWD_STATE_ACTIVE);
// give reader time to wake up and settle
Delay_us((RFIDlerConfig.FrameClock * RFIDlerConfig.RWD_Wake_Period) / 100);
}
// reset timer for timeout
GetTimer_us(RESET);
// align ourselves to reader's bit period by finding the end of a pulse train.
// we can do this by measuring the gaps. when they become significantly different
// sized (more than 25%), we have just switched frequency.
// find the start of a pulse
while(READER_DATA)
if(timeout_us)
if (GetTimer_us(NO_RESET) > timeout_us)
return FALSE;
while(!READER_DATA)
if(timeout_us)
if (GetTimer_us(NO_RESET) > timeout_us)
return FALSE;
while(READER_DATA)
if(timeout_us)
if (GetTimer_us(NO_RESET) > timeout_us)
return FALSE;
// reset timer so we can meausure gap period
GetTimer_us(RESET);
while(!READER_DATA)
if(timeout_us)
if (GetTimer_us(NO_RESET) > timeout_us)
return FALSE;
gaplength= GetTimer_us(RESET);
// now look for a gap that doesn't match
while(42)
{
while(READER_DATA)
if(timeout_us)
if (GetTimer_us(NO_RESET) > timeout_us)
return FALSE;
GetTimer_us(TRUE);
while(!READER_DATA)
if(timeout_us)
if (GetTimer_us(NO_RESET) > timeout_us)
return FALSE;
if(!approx(GetTimer_us(NO_RESET), gaplength, FSK_TOLERANCE))
break;
}
// reset timer for external timeouts
GetTimer_us(RESET);
// start ISR to read FSK data
InitHWReaderISR(CONVERT_TO_TICKS(period) * ticks - 1L, TRUE);
return TRUE;
}
