This introduces a new majoe mode, FPGA_MAJOR_MODE_OFF_LF, which should ONLY be used in sending loops for LF. Basically the PWR_LO is set HIGH in order to discharge voltage faster.
Once sending is over, the normal FPGA_MAJOR_MODE_OFF SHALL be used.
The initial code assumed phase shift modulation only. Lately,
xcorrelation is also used for load modulation. But the initial
the assumption that 11 bits are enough isn't true for load
modulation.
This change extends the registers by 2 bits and compresses the
uper bits to preserve the sensitivity on the lower end.
- Even tough legic tags transmit just AM using xcorrelation
results in a significantly better signal quality.
- Switching from bit bang to a hardware based ssc frees
up CPU time for other tasks e.g. demodulation
- fix: IQ demodulator (FPGA)
- fix: approximately align reader signal delay to tag response delay (FPGA)
- fix: remove deprecated RSSI calculation to improve decoder speed (iso14443b.c)
- fix: better approximation of signal amplitude to avoid false carrier detection (iso14443b.c)
- fix: remove initial power off in iso14443b raw command (iso14443b.c)
- add: enable tracing for iso14443b raw command (iso14443b.c)
- fix: client crashed when checking CRC for incomplete responses (iso14433b.c)
- speeding up snoop to avoid circular buffer overflow
- added some comments for better documentation
- rename functions (iso14443 -> iso14443b)
- remove unused code in hi_read_rx_xcorr.v
- most significant bit of tag data (which happens to be the sign bit)
had been dropped when snooping (FPGA change)
- avoid trying to decode both tag and reader data when snooping (we don't
have the time to do so).
This is a new LF edge detection algorithm for the FPGA.
- It uses a low-pass IIR filter to clean the signal
(see https://fail0verflow.com/blog/2014/proxmark3-fpga-iir-filter.html)
- The algorithm is able to detect consecutive peaks in the same
direction
- It uses an envelope follower to dynamically adjust the peak thresholds
- The main threshold used in the envelope follower can be set from the ARM side
fpga/lf_edge_detect.v,
fpga/lp20khz_1MSa_iir_filter.v,
fpga/min_max_tracker.v: New file.
fpga/lo_edge_detect.v, fpga/fpga_lf.v: Modify accordingly.
armsrc/apps.h (FPGA_CMD_SET_USER_BYTE1,
FPGA_CMD_SET_EDGE_DETECT_THRESHOLD): New FPGA command.
fpga/fpga_lf.v: Modify accordingly/Add a 8bit user register.
fpga/fpga_lf.bit: Update accordingly.
fpga/tests: New directory for testbenches
fpga/tests/Makefile: New file. It compiles the testbenches
and runs all the tests by default (comparing with the golden output)
fpga/tests/tb_lp20khz_1MSa_iir_filter.v,
fpga/tests/tb_min_max_tracker.v,
fpga/tests/tb_lf_edge_detect.v: New testbenches
fpga/tests/plot_edgedetect.py: New script to plot the results from
the edge detection tests.
fpga/tests/tb_data: New directory for data and golden outputs
