X-Git-Url: https://git.zerfleddert.de/cgi-bin/gitweb.cgi/proxmark3-svn/blobdiff_plain/6658905f18a1eebc148836f26c731dea9c1377dc..refs/pull/938/head:/fpga/hi_simulate.v diff --git a/fpga/hi_simulate.v b/fpga/hi_simulate.v index d0a71176..7627e932 100644 --- a/fpga/hi_simulate.v +++ b/fpga/hi_simulate.v @@ -1,106 +1,145 @@ -//----------------------------------------------------------------------------- -// Pretend to be an ISO 14443 tag. We will do this by alternately short- -// circuiting and open-circuiting the antenna coil, with the tri-state -// pins. -// -// We communicate over the SSP, as a bitstream (i.e., might as well be -// unframed, though we still generate the word sync signal). The output -// (ARM -> FPGA) tells us whether to modulate or not. The input (FPGA -// -> ARM) is us using the A/D as a fancy comparator; this is with -// (software-added) hysteresis, to undo the high-pass filter. -// -// At this point only Type A is implemented. This means that we are using a -// bit rate of 106 kbit/s, or fc/128. Oversample by 4, which ought to make -// things practical for the ARM (fc/32, 423.8 kbits/s, ~50 kbytes/s) -// -// Jonathan Westhues, October 2006 -//----------------------------------------------------------------------------- - -module hi_simulate( - pck0, ck_1356meg, ck_1356megb, - pwr_lo, pwr_hi, pwr_oe1, pwr_oe2, pwr_oe3, pwr_oe4, - adc_d, adc_clk, - ssp_frame, ssp_din, ssp_dout, ssp_clk, - cross_hi, cross_lo, - dbg, - mod_type -); - input pck0, ck_1356meg, ck_1356megb; - output pwr_lo, pwr_hi, pwr_oe1, pwr_oe2, pwr_oe3, pwr_oe4; - input [7:0] adc_d; - output adc_clk; - input ssp_dout; - output ssp_frame, ssp_din, ssp_clk; - input cross_hi, cross_lo; - output dbg; - input [2:0] mod_type; - -// Power amp goes between LOW and tri-state, so pwr_hi (and pwr_lo) can -// always be low. -assign pwr_hi = 1'b0; -assign pwr_lo = 1'b0; - -// The comparator with hysteresis on the output from the peak detector. -reg after_hysteresis; -assign adc_clk = ck_1356meg; - -always @(negedge adc_clk) -begin - if(& adc_d[7:5]) after_hysteresis = 1'b1; - else if(~(| adc_d[7:5])) after_hysteresis = 1'b0; -end - -// Divide 13.56 MHz by 32 to produce the SSP_CLK -reg [4:0] ssp_clk_divider; -always @(posedge adc_clk) - ssp_clk_divider <= (ssp_clk_divider + 1); -assign ssp_clk = ssp_clk_divider[4]; - -// Divide SSP_CLK by 8 to produce the byte framing signal; the phase of -// this is arbitrary, because it's just a bitstream. -// One nasty issue, though: I can't make it work with both rx and tx at -// once. The phase wrt ssp_clk must be changed. TODO to find out why -// that is and make a better fix. -reg [2:0] ssp_frame_divider_to_arm; -always @(posedge ssp_clk) - ssp_frame_divider_to_arm <= (ssp_frame_divider_to_arm + 1); -reg [2:0] ssp_frame_divider_from_arm; -always @(negedge ssp_clk) - ssp_frame_divider_from_arm <= (ssp_frame_divider_from_arm + 1); - -reg ssp_frame; -always @(ssp_frame_divider_to_arm or ssp_frame_divider_from_arm or mod_type) - if(mod_type == 3'b000) // not modulating, so listening, to ARM - ssp_frame = (ssp_frame_divider_to_arm == 3'b000); - else - ssp_frame = (ssp_frame_divider_from_arm == 3'b000); - -// Synchronize up the after-hysteresis signal, to produce DIN. -reg ssp_din; -always @(posedge ssp_clk) - ssp_din = after_hysteresis; - -// Modulating carrier frequency is fc/16, reuse ssp_clk divider for that -reg modulating_carrier; -always @(mod_type or ssp_clk or ssp_dout) - if(mod_type == 3'b000) - modulating_carrier <= 1'b0; // no modulation - else if(mod_type == 3'b001) - modulating_carrier <= ssp_dout ^ ssp_clk_divider[3]; // XOR means BPSK - else - modulating_carrier <= 1'b0; // yet unused - -// This one is all LF, so doesn't matter -assign pwr_oe2 = modulating_carrier; - -// Toggle only one of these, since we are already producing much deeper -// modulation than a real tag would. -assign pwr_oe1 = modulating_carrier; -assign pwr_oe4 = modulating_carrier; - -// This one is always on, so that we can watch the carrier. -assign pwr_oe3 = 1'b0; - -assign dbg = after_hysteresis; - -endmodule +//----------------------------------------------------------------------------- +// Pretend to be an ISO 14443 tag. We will do this by alternately short- +// circuiting and open-circuiting the antenna coil, with the tri-state +// pins. +// +// We communicate over the SSP, as a bitstream (i.e., might as well be +// unframed, though we still generate the word sync signal). The output +// (ARM -> FPGA) tells us whether to modulate or not. The input (FPGA +// -> ARM) is us using the A/D as a fancy comparator; this is with +// (software-added) hysteresis, to undo the high-pass filter. +// +// At this point only Type A is implemented. This means that we are using a +// bit rate of 106 kbit/s, or fc/128. Oversample by 4, which ought to make +// things practical for the ARM (fc/32, 423.8 kbits/s, ~50 kbytes/s) +// +// Jonathan Westhues, October 2006 +//----------------------------------------------------------------------------- + +module hi_simulate( + ck_1356meg, + pwr_lo, pwr_hi, pwr_oe1, pwr_oe2, pwr_oe3, pwr_oe4, + adc_d, adc_clk, + ssp_frame, ssp_din, ssp_dout, ssp_clk, + dbg, + mod_type +); + input ck_1356meg; + output pwr_lo, pwr_hi, pwr_oe1, pwr_oe2, pwr_oe3, pwr_oe4; + input [7:0] adc_d; + output adc_clk; + input ssp_dout; + output ssp_frame, ssp_din, ssp_clk; + output dbg; + input [3:0] mod_type; + +assign adc_clk = ck_1356meg; + +// The comparator with hysteresis on the output from the peak detector. +reg after_hysteresis; +reg [11:0] has_been_low_for; + +always @(negedge adc_clk) +begin + if (& adc_d[7:5]) after_hysteresis <= 1'b1; // if (adc_d >= 224) + else if (~(| adc_d[7:5])) after_hysteresis <= 1'b0; // if (adc_d <= 31) + + if (adc_d >= 224) + begin + has_been_low_for <= 12'd0; + end + else + begin + if (has_been_low_for == 12'd4095) + begin + has_been_low_for <= 12'd0; + after_hysteresis <= 1'b1; + end + else + begin + has_been_low_for <= has_been_low_for + 1; + end + end +end + + +// Divide 13.56 MHz to produce various frequencies for SSP_CLK +// and modulation. +reg [8:0] ssp_clk_divider; + +always @(negedge adc_clk) + ssp_clk_divider <= (ssp_clk_divider + 1); + +reg ssp_clk; + +always @(negedge adc_clk) +begin + if (mod_type == `FPGA_HF_SIMULATOR_MODULATE_424K_8BIT) + // Get bit every at 53KHz (every 8th carrier bit of 424kHz) + ssp_clk <= ~ssp_clk_divider[7]; + else if (mod_type == `FPGA_HF_SIMULATOR_MODULATE_212K) + // Get next bit at 212kHz + ssp_clk <= ~ssp_clk_divider[5]; + else + // Get next bit at 424Khz + ssp_clk <= ~ssp_clk_divider[4]; +end + + +// Produce the byte framing signal; the phase of this signal +// is arbitrary, because it's just a bit stream in this module. +reg ssp_frame; +always @(negedge adc_clk) +begin + if (mod_type == `FPGA_HF_SIMULATOR_MODULATE_212K) + begin + if (ssp_clk_divider[8:5] == 4'd1) + ssp_frame <= 1'b1; + if (ssp_clk_divider[8:5] == 4'd5) + ssp_frame <= 1'b0; + end + else + begin + if (ssp_clk_divider[7:4] == 4'd1) + ssp_frame <= 1'b1; + if (ssp_clk_divider[7:4] == 4'd5) + ssp_frame <= 1'b0; + end +end + + +// Synchronize up the after-hysteresis signal, to produce DIN. +reg ssp_din; +always @(posedge ssp_clk) + ssp_din = after_hysteresis; + +// Modulating carrier frequency is fc/64 (212kHz) to fc/16 (848kHz). Reuse ssp_clk divider for that. +reg modulating_carrier; +always @(*) + if (mod_type == `FPGA_HF_SIMULATOR_NO_MODULATION) + modulating_carrier <= 1'b0; // no modulation + else if (mod_type == `FPGA_HF_SIMULATOR_MODULATE_BPSK) + modulating_carrier <= ssp_dout ^ ssp_clk_divider[3]; // XOR means BPSK + else if (mod_type == `FPGA_HF_SIMULATOR_MODULATE_212K) + modulating_carrier <= ssp_dout & ssp_clk_divider[5]; // switch 212kHz subcarrier on/off + else if (mod_type == `FPGA_HF_SIMULATOR_MODULATE_424K || mod_type == `FPGA_HF_SIMULATOR_MODULATE_424K_8BIT) + modulating_carrier <= ssp_dout & ssp_clk_divider[4]; // switch 424kHz modulation on/off + else + modulating_carrier <= 1'b0; // yet unused + + +// Load modulation. Toggle only one of these, since we are already producing much deeper +// modulation than a real tag would. +assign pwr_hi = 1'b0; // HF antenna connected to GND +assign pwr_oe3 = 1'b0; // 10k Load +assign pwr_oe1 = 1'b0; // 33 Ohms Load +assign pwr_oe4 = modulating_carrier; // 33 Ohms Load + +// This is all LF and doesn't matter +assign pwr_lo = 1'b0; +assign pwr_oe2 = 1'b0; + + +assign dbg = ssp_frame; + +endmodule