fpga/fpga_hf.v

   1 //-----------------------------------------------------------------------------
   2 // The FPGA is responsible for interfacing between the A/D, the coil drivers,
   3 // and the ARM. In the low-frequency modes it passes the data straight
   4 // through, so that the ARM gets raw A/D samples over the SSP. In the high-
   5 // frequency modes, the FPGA might perform some demodulation first, to
   6 // reduce the amount of data that we must send to the ARM.
   7 //
   8 // I am not really an FPGA/ASIC designer, so I am sure that a lot of this
   9 // could be improved.
  10 //
  11 // Jonathan Westhues, March 2006
  12 // Added ISO14443-A support by Gerhard de Koning Gans, April 2008
  13 // iZsh <izsh at fail0verflow.com>, June 2014
  14 //-----------------------------------------------------------------------------
  15
  16 `include "hi_read_tx.v"
  17 `include "hi_read_rx_xcorr.v"
  18 `include "hi_simulate.v"
  19 `include "hi_iso14443a.v"
  20 `include "util.v"
  21
  22 module fpga_hf(
  23         input spck, output miso, input mosi, input ncs,
  24         input pck0, input ck_1356meg, input ck_1356megb,
  25         output pwr_lo, output pwr_hi,
  26         output pwr_oe1, output pwr_oe2, output pwr_oe3, output pwr_oe4,
  27         input [7:0] adc_d, output adc_clk, output adc_noe,
  28         output ssp_frame, output ssp_din, input ssp_dout, output ssp_clk,
  29         input cross_hi, input cross_lo,
  30         output dbg
  31 );
  32
  33 //-----------------------------------------------------------------------------
  34 // The SPI receiver. This sets up the configuration word, which the rest of
  35 // the logic looks at to determine how to connect the A/D and the coil
  36 // drivers (i.e., which section gets it). Also assign some symbolic names
  37 // to the configuration bits, for use below.
  38 //-----------------------------------------------------------------------------
  39
  40 reg [15:0] shift_reg;
  41 reg [7:0] conf_word;
  42
  43 // We switch modes between transmitting to the 13.56 MHz tag and receiving
  44 // from it, which means that we must make sure that we can do so without
  45 // glitching, or else we will glitch the transmitted carrier.
  46 always @(posedge ncs)
  47 begin
  48         case(shift_reg[15:12])
  49                 4'b0001: conf_word <= shift_reg[7:0];           // FPGA_CMD_SET_CONFREG
  50         endcase
  51 end
  52
  53 always @(posedge spck)
  54 begin
  55         if(~ncs)
  56         begin
  57                 shift_reg[15:1] <= shift_reg[14:0];
  58                 shift_reg[0] <= mosi;
  59         end
  60 end
  61
  62 wire [2:0] major_mode;
  63 assign major_mode = conf_word[7:5];
  64
  65 // For the high-frequency transmit configuration: modulation depth, either
  66 // 100% (just quite driving antenna, steady LOW), or shallower (tri-state
  67 // some fraction of the buffers)
  68 wire hi_read_tx_shallow_modulation = conf_word[0];
  69
  70 // For the high-frequency receive correlator: frequency against which to
  71 // correlate.
  72 wire hi_read_rx_xcorr_848 = conf_word[0];
  73 // and whether to drive the coil (reader) or just short it (snooper)
  74 wire hi_read_rx_xcorr_snoop = conf_word[1];
  75
  76 // Divide the expected subcarrier frequency for hi_read_rx_xcorr by 4
  77 wire hi_read_rx_xcorr_quarter = conf_word[2];
  78
  79 // For the high-frequency simulated tag: what kind of modulation to use.
  80 wire [2:0] hi_simulate_mod_type = conf_word[2:0];
  81
  82 //-----------------------------------------------------------------------------
  83 // And then we instantiate the modules corresponding to each of the FPGA's
  84 // major modes, and use muxes to connect the outputs of the active mode to
  85 // the output pins.
  86 //-----------------------------------------------------------------------------
  87
  88 hi_read_tx ht(
  89         pck0, ck_1356meg, ck_1356megb,
  90         ht_pwr_lo, ht_pwr_hi, ht_pwr_oe1, ht_pwr_oe2, ht_pwr_oe3, ht_pwr_oe4,
  91         adc_d, ht_adc_clk,
  92         ht_ssp_frame, ht_ssp_din, ssp_dout, ht_ssp_clk,
  93         cross_hi, cross_lo,
  94         ht_dbg,
  95         hi_read_tx_shallow_modulation
  96 );
  97
  98 hi_read_rx_xcorr hrxc(
  99         pck0, ck_1356meg, ck_1356megb,
 100         hrxc_pwr_lo, hrxc_pwr_hi, hrxc_pwr_oe1, hrxc_pwr_oe2, hrxc_pwr_oe3,     hrxc_pwr_oe4,
 101         adc_d, hrxc_adc_clk,
 102         hrxc_ssp_frame, hrxc_ssp_din, ssp_dout, hrxc_ssp_clk,
 103         cross_hi, cross_lo,
 104         hrxc_dbg,
 105         hi_read_rx_xcorr_848, hi_read_rx_xcorr_snoop, hi_read_rx_xcorr_quarter
 106 );
 107
 108 hi_simulate hs(
 109         pck0, ck_1356meg, ck_1356megb,
 110         hs_pwr_lo, hs_pwr_hi, hs_pwr_oe1, hs_pwr_oe2, hs_pwr_oe3, hs_pwr_oe4,
 111         adc_d, hs_adc_clk,
 112         hs_ssp_frame, hs_ssp_din, ssp_dout, hs_ssp_clk,
 113         cross_hi, cross_lo,
 114         hs_dbg,
 115         hi_simulate_mod_type
 116 );
 117
 118 hi_iso14443a hisn(
 119         pck0, ck_1356meg, ck_1356megb,
 120         hisn_pwr_lo, hisn_pwr_hi, hisn_pwr_oe1, hisn_pwr_oe2, hisn_pwr_oe3,     hisn_pwr_oe4,
 121         adc_d, hisn_adc_clk,
 122         hisn_ssp_frame, hisn_ssp_din, ssp_dout, hisn_ssp_clk,
 123         cross_hi, cross_lo,
 124         hisn_dbg,
 125         hi_simulate_mod_type
 126 );
 127
 128 // Major modes:
 129
 130 //   000 --  HF reader, transmitting to tag; modulation depth selectable
 131 //   001 --  HF reader, receiving from tag, correlating as it goes; frequency selectable
 132 //   010 --  HF simulated tag
 133 //   011 --  HF ISO14443-A
 134 //   111 --  everything off
 135
 136 mux8 mux_ssp_clk                (major_mode, ssp_clk,   ht_ssp_clk,   hrxc_ssp_clk,   hs_ssp_clk,   hisn_ssp_clk,   1'b0, 1'b0, 1'b0, 1'b0);
 137 mux8 mux_ssp_din                (major_mode, ssp_din,   ht_ssp_din,   hrxc_ssp_din,   hs_ssp_din,   hisn_ssp_din,   1'b0, 1'b0, 1'b0, 1'b0);
 138 mux8 mux_ssp_frame              (major_mode, ssp_frame, ht_ssp_frame, hrxc_ssp_frame, hs_ssp_frame, hisn_ssp_frame, 1'b0, 1'b0, 1'b0, 1'b0);
 139 mux8 mux_pwr_oe1                (major_mode, pwr_oe1,   ht_pwr_oe1,   hrxc_pwr_oe1,   hs_pwr_oe1,   hisn_pwr_oe1,   1'b0, 1'b0, 1'b0, 1'b0);
 140 mux8 mux_pwr_oe2                (major_mode, pwr_oe2,   ht_pwr_oe2,   hrxc_pwr_oe2,   hs_pwr_oe2,   hisn_pwr_oe2,   1'b0, 1'b0, 1'b0, 1'b0);
 141 mux8 mux_pwr_oe3                (major_mode, pwr_oe3,   ht_pwr_oe3,   hrxc_pwr_oe3,   hs_pwr_oe3,   hisn_pwr_oe3,   1'b0, 1'b0, 1'b0, 1'b0);
 142 mux8 mux_pwr_oe4                (major_mode, pwr_oe4,   ht_pwr_oe4,   hrxc_pwr_oe4,   hs_pwr_oe4,   hisn_pwr_oe4,   1'b0, 1'b0, 1'b0, 1'b0);
 143 mux8 mux_pwr_lo                 (major_mode, pwr_lo,    ht_pwr_lo,    hrxc_pwr_lo,    hs_pwr_lo,    hisn_pwr_lo,    1'b0, 1'b0, 1'b0, 1'b0);
 144 mux8 mux_pwr_hi                 (major_mode, pwr_hi,    ht_pwr_hi,    hrxc_pwr_hi,    hs_pwr_hi,    hisn_pwr_hi,    1'b0, 1'b0, 1'b0, 1'b0);
 145 mux8 mux_adc_clk                (major_mode, adc_clk,   ht_adc_clk,   hrxc_adc_clk,   hs_adc_clk,   hisn_adc_clk,   1'b0, 1'b0, 1'b0, 1'b0);
 146 mux8 mux_dbg                    (major_mode, dbg,       ht_dbg,       hrxc_dbg,       hs_dbg,       hisn_dbg,       1'b0, 1'b0, 1'b0, 1'b0);
 147
 148 // In all modes, let the ADC's outputs be enabled.
 149 assign adc_noe = 1'b0;
 150
 151 endmodule