* rework iso14443b device functions
* hf_read_rx_xcorr.v: transfer i/q pair in one 16bit frame
* hi_read_tx.v: invert ssp_dout. When nothing is transferred (ssp_dout=0), this results in no modulation (carrier on)
* adjust arm sources accordingly
* iso14443b.c: switch off carrier after hf 14b sri512read and hf 14b srix4kread
* iso14443b.c: fix DMA circular buffer handling
* Legic: rewrite reader to use xcorrelation and precise timing
- Even tough Legic tags transmit just AM, receiving 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. prng and demodulation
- Having all times based on a fixed ts, results in perfect
rwd-tag synchronization without magic +/- calculations.
* hi_read_tx: remove jerry-riged hysteresis based receiver
- This feature got obsolete by a x-correlation based receiver.
* Legic: adjusted sampling to new ssp clock speed
- Sampling is 4 times faster and pipeline daly reduced to 1/4.
The new code samples each bit earyler to account for the
shorter pipeline. That introduced bit errors by leeking the
next bit into the current one.
* Legic: average 8 samples for better noise rejection.
* Update CHANGELOG.md
It is identical to the popular 20081211, with the doob addition (20090301), a
linux client, and two additional commands for LF analysis. Let me know if
you find issues here!
