-void AcquireRawAdcSamples125k(BOOL at134khz)
-{
- if(at134khz) {
- FpgaSendCommand(FPGA_CMD_SET_DIVISOR, 88); //134.8Khz
- FpgaWriteConfWord(FPGA_MAJOR_MODE_LF_READER);
- } else {
- FpgaSendCommand(FPGA_CMD_SET_DIVISOR, 95); //125Khz
- FpgaWriteConfWord(FPGA_MAJOR_MODE_LF_READER);
- }
-
- // Connect the A/D to the peak-detected low-frequency path.
- SetAdcMuxFor(GPIO_MUXSEL_LOPKD);
-
- // Give it a bit of time for the resonant antenna to settle.
- SpinDelay(50);
-
- // Now set up the SSC to get the ADC samples that are now streaming at us.
- FpgaSetupSsc();
-
- // Now call the acquisition routine
- DoAcquisition125k(at134khz);
-}
-
-// split into two routines so we can avoid timing issues after sending commands //
-void DoAcquisition125k(BOOL at134khz)
-{
- BYTE *dest = (BYTE *)BigBuf;
- int n = sizeof(BigBuf);
- int i;
-
- memset(dest,0,n);
- i = 0;
- for(;;) {
- if(SSC_STATUS & (SSC_STATUS_TX_READY)) {
- SSC_TRANSMIT_HOLDING = 0x43;
- LED_D_ON();
- }
- if(SSC_STATUS & (SSC_STATUS_RX_READY)) {
- dest[i] = (BYTE)SSC_RECEIVE_HOLDING;
- i++;
- LED_D_OFF();
- if(i >= n) {
- break;
- }
- }
- }
- DbpIntegers(dest[0], dest[1], at134khz);
-}
-
-void ModThenAcquireRawAdcSamples125k(int delay_off,int period_0,int period_1,BYTE *command)
-{
- BOOL at134khz;
-
- // see if 'h' was specified
- if(command[strlen((char *) command) - 1] == 'h')
- at134khz= TRUE;
- else
- at134khz= FALSE;
-
- if(at134khz) {
- FpgaSendCommand(FPGA_CMD_SET_DIVISOR, 88); //134.8Khz
- FpgaWriteConfWord(FPGA_MAJOR_MODE_LF_READER);
- } else {
- FpgaSendCommand(FPGA_CMD_SET_DIVISOR, 95); //125Khz
- FpgaWriteConfWord(FPGA_MAJOR_MODE_LF_READER);
- }
-
- // Give it a bit of time for the resonant antenna to settle.
- SpinDelay(50);
-
- // Now set up the SSC to get the ADC samples that are now streaming at us.
- FpgaSetupSsc();
-
- // now modulate the reader field
- while(*command != '\0' && *command != ' ')
- {
- FpgaWriteConfWord(FPGA_MAJOR_MODE_OFF);
- LED_D_OFF();
- SpinDelayUs(delay_off);
- if(at134khz) {
- FpgaSendCommand(FPGA_CMD_SET_DIVISOR, 88); //134.8Khz
- FpgaWriteConfWord(FPGA_MAJOR_MODE_LF_READER);
- } else {
- FpgaSendCommand(FPGA_CMD_SET_DIVISOR, 95); //125Khz
- FpgaWriteConfWord(FPGA_MAJOR_MODE_LF_READER);
- }
- LED_D_ON();
- if(*(command++) == '0')
- SpinDelayUs(period_0);
- else
- SpinDelayUs(period_1);
- }
- FpgaWriteConfWord(FPGA_MAJOR_MODE_OFF);
- LED_D_OFF();
- SpinDelayUs(delay_off);
- if(at134khz) {
- FpgaSendCommand(FPGA_CMD_SET_DIVISOR, 88); //134.8Khz
- FpgaWriteConfWord(FPGA_MAJOR_MODE_LF_READER);
- } else {
- FpgaSendCommand(FPGA_CMD_SET_DIVISOR, 95); //125Khz
- FpgaWriteConfWord(FPGA_MAJOR_MODE_LF_READER);
- }
-
- // now do the read
- DoAcquisition125k(at134khz);
-}
-
-//-----------------------------------------------------------------------------
-// Read a TI-type tag. We assume that the tag has already been illuminated,
-// and that the exciting signal has been turned off. That means that we just
-// acquire the `one-bit DAC' bits from the comparator.
-//-----------------------------------------------------------------------------
-void AcquireTiType(void)
-{
- int i;
- int n = 4000;
-
- // clear buffer
- memset(BigBuf,0,sizeof(BigBuf));
-
- // Set up the synchronous serial port
- PIO_DISABLE = (1<<GPIO_SSC_DIN);
- PIO_PERIPHERAL_A_SEL = (1<<GPIO_SSC_DIN);
-
- SSC_CONTROL = SSC_CONTROL_RESET;
- SSC_CONTROL = SSC_CONTROL_RX_ENABLE | SSC_CONTROL_TX_ENABLE;
-
- // Sample at 2 Mbit/s, so TI tags are 16.2 vs. 14.9 clocks long
- // 48/2 = 24 MHz clock must be divided by 12
- SSC_CLOCK_DIVISOR = 12;
-
- SSC_RECEIVE_CLOCK_MODE = SSC_CLOCK_MODE_SELECT(0);
- SSC_RECEIVE_FRAME_MODE = SSC_FRAME_MODE_BITS_IN_WORD(32) | SSC_FRAME_MODE_MSB_FIRST;
- SSC_TRANSMIT_CLOCK_MODE = 0;
- SSC_TRANSMIT_FRAME_MODE = 0;
-
- i = 0;
- for(;;) {
- if(SSC_STATUS & SSC_STATUS_RX_READY) {
- BigBuf[i] = SSC_RECEIVE_HOLDING; // store 32 bit values in buffer
- i++; if(i >= n) return;
- }
- WDT_HIT();
- }
-}
-
-void AcquireRawBitsTI(void)
-{
- LED_D_ON();
- // TI tags charge at 134.2Khz
- FpgaSendCommand(FPGA_CMD_SET_DIVISOR, 88); //134.8Khz
- FpgaWriteConfWord(FPGA_MAJOR_MODE_LF_READER);
-
- // Charge TI tag for 50ms.
- SpinDelay(50);
- LED_D_OFF();
-
- LED_A_ON();
- // Place FPGA in passthrough mode so as to stop driving the LF coil,
- // in this mode the CROSS_LO line connects to SSP_DIN
- FpgaWriteConfWord(FPGA_MAJOR_MODE_LF_PASSTHRU);
-
- // get TI tag data into the buffer
- AcquireTiType();
-
- FpgaWriteConfWord(FPGA_MAJOR_MODE_OFF);
- LED_A_OFF();
-}
-