X-Git-Url: http://git.zerfleddert.de/cgi-bin/gitweb.cgi/proxmark3-svn/blobdiff_plain/9f596ec7ac317c7e0e6d60610a20fb1f3feba194..d9de20fa4bb0a36052927b55c4185caa204c5c4d:/fpga/hi_read_rx_xcorr.v diff --git a/fpga/hi_read_rx_xcorr.v b/fpga/hi_read_rx_xcorr.v index 8233960f..503c8d67 100644 --- a/fpga/hi_read_rx_xcorr.v +++ b/fpga/hi_read_rx_xcorr.v @@ -10,7 +10,7 @@ module hi_read_rx_xcorr( ssp_frame, ssp_din, ssp_dout, ssp_clk, cross_hi, cross_lo, dbg, - xcorr_is_848, snoop, xcorr_quarter_freq + xcorr_is_848, snoop, xcorr_quarter_freq, hi_read_rx_xcorr_amplitude ); input pck0, ck_1356meg, ck_1356megb; output pwr_lo, pwr_hi, pwr_oe1, pwr_oe2, pwr_oe3, pwr_oe4; @@ -20,7 +20,7 @@ module hi_read_rx_xcorr( output ssp_frame, ssp_din, ssp_clk; input cross_hi, cross_lo; output dbg; - input xcorr_is_848, snoop, xcorr_quarter_freq; + input xcorr_is_848, snoop, xcorr_quarter_freq, hi_read_rx_xcorr_amplitude; // Carrier is steady on through this, unless we're snooping. assign pwr_hi = ck_1356megb & (~snoop); @@ -83,11 +83,46 @@ reg signed [13:0] corr_q_accum; // we will report maximum 8 significant bits reg signed [7:0] corr_i_out; reg signed [7:0] corr_q_out; + // clock and frame signal for communication to ARM reg ssp_clk; reg ssp_frame; + +// the amplitude of the subcarrier is sqrt(ci^2 + cq^2). +// approximate by amplitude = max(|ci|,|cq|) + 1/2*min(|ci|,|cq|) +reg [13:0] corr_amplitude, abs_ci, abs_cq, max_ci_cq, min_ci_cq; + + +always @(corr_i_accum or corr_q_accum) +begin + if (corr_i_accum[13] == 1'b0) + abs_ci <= corr_i_accum; + else + abs_ci <= -corr_i_accum; + + if (corr_q_accum[13] == 1'b0) + abs_cq <= corr_q_accum; + else + abs_cq <= -corr_q_accum; + + if (abs_ci > abs_cq) + begin + max_ci_cq <= abs_ci; + min_ci_cq <= abs_cq; + end + else + begin + max_ci_cq <= abs_cq; + min_ci_cq <= abs_ci; + end + + corr_amplitude <= max_ci_cq + min_ci_cq/2; + +end + + // The subcarrier reference signals reg subcarrier_I; reg subcarrier_Q; @@ -110,52 +145,75 @@ begin subcarrier_Q = ~(corr_i_cnt[4] ^ corr_i_cnt[3]); end end - + + // ADC data appears on the rising edge, so sample it on the falling edge always @(negedge adc_clk) begin // These are the correlators: we correlate against in-phase and quadrature - // versions of our reference signal, and keep the (signed) result to - // send out later over the SSP. + // versions of our reference signal, and keep the (signed) results or the + // resulting amplitude to send out later over the SSP. if(corr_i_cnt == 6'd0) begin if(snoop) begin - // Send 7 most significant bits of tag signal (signed), plus 1 bit reader signal - if (corr_i_accum[13:11] == 3'b000 || corr_i_accum[13:11] == 3'b111) - corr_i_out <= {corr_i_accum[11:5], after_hysteresis_prev_prev}; - else // truncate to maximum value - if (corr_i_accum[13] == 1'b0) - corr_i_out <= {7'b0111111, after_hysteresis_prev_prev}; - else - corr_i_out <= {7'b1000000, after_hysteresis_prev_prev}; - if (corr_q_accum[13:11] == 3'b000 || corr_q_accum[13:11] == 3'b111) - corr_q_out <= {corr_q_accum[11:5], after_hysteresis_prev}; - else // truncate to maximum value - if (corr_q_accum[13] == 1'b0) - corr_q_out <= {7'b0111111, after_hysteresis_prev}; - else - corr_q_out <= {7'b1000000, after_hysteresis_prev}; - after_hysteresis_prev_prev <= after_hysteresis; + if (hi_read_rx_xcorr_amplitude) + begin + // send amplitude plus 2 bits reader signal + corr_i_out <= corr_amplitude[13:6]; + corr_q_out <= {corr_amplitude[5:0], after_hysteresis_prev_prev, after_hysteresis_prev}; + end + else + begin + // Send 7 most significant bits of in phase tag signal (signed), plus 1 bit reader signal + if (corr_i_accum[13:11] == 3'b000 || corr_i_accum[13:11] == 3'b111) + corr_i_out <= {corr_i_accum[11:5], after_hysteresis_prev_prev}; + else // truncate to maximum value + if (corr_i_accum[13] == 1'b0) + corr_i_out <= {7'b0111111, after_hysteresis_prev_prev}; + else + corr_i_out <= {7'b1000000, after_hysteresis_prev_prev}; + // Send 7 most significant bits of quadrature phase tag signal (signed), plus 1 bit reader signal + if (corr_q_accum[13:11] == 3'b000 || corr_q_accum[13:11] == 3'b111) + corr_q_out <= {corr_q_accum[11:5], after_hysteresis_prev}; + else // truncate to maximum value + if (corr_q_accum[13] == 1'b0) + corr_q_out <= {7'b0111111, after_hysteresis_prev}; + else + corr_q_out <= {7'b1000000, after_hysteresis_prev}; + end end else begin - // Send 8 bits of tag signal - if (corr_i_accum[13:11] == 3'b000 || corr_i_accum[13:11] == 3'b111) - corr_i_out <= corr_i_accum[11:4]; - else // truncate to maximum value - if (corr_i_accum[13] == 1'b0) - corr_i_out <= 8'b01111111; - else - corr_i_out <= 8'b10000000; - if (corr_q_accum[13:11] == 3'b000 || corr_q_accum[13:11] == 3'b111) - corr_q_out <= corr_q_accum[11:4]; - else // truncate to maximum value - if (corr_q_accum[13] == 1'b0) - corr_q_out <= 8'b01111111; - else - corr_q_out <= 8'b10000000; + if (hi_read_rx_xcorr_amplitude) + begin + // send amplitude + corr_i_out <= {2'b00, corr_amplitude[13:8]}; + corr_q_out <= corr_amplitude[7:0]; + end + else + begin + // Send 8 bits of in phase tag signal + if (corr_i_accum[13:11] == 3'b000 || corr_i_accum[13:11] == 3'b111) + corr_i_out <= corr_i_accum[11:4]; + else // truncate to maximum value + if (corr_i_accum[13] == 1'b0) + corr_i_out <= 8'b01111111; + else + corr_i_out <= 8'b10000000; + // Send 8 bits of quadrature phase tag signal + if (corr_q_accum[13:11] == 3'b000 || corr_q_accum[13:11] == 3'b111) + corr_q_out <= corr_q_accum[11:4]; + else // truncate to maximum value + if (corr_q_accum[13] == 1'b0) + corr_q_out <= 8'b01111111; + else + corr_q_out <= 8'b10000000; + end end + + // for each Q/I pair report two reader signal samples when sniffing. Store the 1st. + after_hysteresis_prev_prev <= after_hysteresis; // Initialize next correlation. // Both I and Q reference signals are high when corr_i_nct == 0. Therefore need to accumulate. corr_i_accum <= $signed({1'b0,adc_d}); @@ -172,16 +230,16 @@ begin corr_q_accum <= corr_q_accum + $signed({1'b0,adc_d}); else corr_q_accum <= corr_q_accum - $signed({1'b0,adc_d}); - end - // for each Q/I pair report two reader signal samples when sniffing + // for each Q/I pair report two reader signal samples when sniffing. Store the 2nd. if(corr_i_cnt == 6'd32) after_hysteresis_prev <= after_hysteresis; // Then the result from last time is serialized and send out to the ARM. // We get one report each cycle, and each report is 16 bits, so the - // ssp_clk should be the adc_clk divided by 64/16 = 4. + // ssp_clk should be the adc_clk divided by 64/16 = 4. + // ssp_clk frequency = 13,56MHz / 4 = 3.39MHz if(corr_i_cnt[1:0] == 2'b10) ssp_clk <= 1'b0;