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;
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);
// 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;
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});
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;
projects / proxmark3-svn / blobdiff