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.
 
   8 // I am not really an FPGA/ASIC designer, so I am sure that a lot of this
 
  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 //-----------------------------------------------------------------------------
 
  16 `include "hi_read_tx.v"
 
  17 `include "hi_read_rx_xcorr.v"
 
  18 `include "hi_simulate.v"
 
  19 `include "hi_iso14443a.v"
 
  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,
 
  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 //-----------------------------------------------------------------------------
 
  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.
 
  48         case(shift_reg[15:12])
 
  49                 4'b0001: conf_word <= shift_reg[7:0];           // FPGA_CMD_SET_CONFREG
 
  53 always @(posedge spck)
 
  57                 shift_reg[15:1] <= shift_reg[14:0];
 
  62 wire [2:0] major_mode;
 
  63 assign major_mode = conf_word[7:5];
 
  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];
 
  70 // For the high-frequency receive correlator:
 
  71 // whether to drive the coil (reader) or just short it (snooper)
 
  72 wire hi_read_rx_xcorr_snoop = conf_word[1];
 
  74 // For the high-frequency simulated tag: what kind of modulation to use.
 
  75 wire [2:0] hi_simulate_mod_type = conf_word[2:0];
 
  77 //-----------------------------------------------------------------------------
 
  78 // And then we instantiate the modules corresponding to each of the FPGA's
 
  79 // major modes, and use muxes to connect the outputs of the active mode to
 
  81 //-----------------------------------------------------------------------------
 
  84         pck0, ck_1356meg, ck_1356megb,
 
  85         ht_pwr_lo, ht_pwr_hi, ht_pwr_oe1, ht_pwr_oe2, ht_pwr_oe3, ht_pwr_oe4,
 
  87         ht_ssp_frame, ht_ssp_din, ssp_dout, ht_ssp_clk,
 
  90         hi_read_tx_shallow_modulation
 
  93 hi_read_rx_xcorr hrxc(
 
  94         pck0, ck_1356meg, ck_1356megb,
 
  95         hrxc_pwr_lo, hrxc_pwr_hi, hrxc_pwr_oe1, hrxc_pwr_oe2, hrxc_pwr_oe3,     hrxc_pwr_oe4,
 
  97         hrxc_ssp_frame, hrxc_ssp_din, ssp_dout, hrxc_ssp_clk,
 
 100         hi_read_rx_xcorr_snoop
 
 104         pck0, ck_1356meg, ck_1356megb,
 
 105         hs_pwr_lo, hs_pwr_hi, hs_pwr_oe1, hs_pwr_oe2, hs_pwr_oe3, hs_pwr_oe4,
 
 107         hs_ssp_frame, hs_ssp_din, ssp_dout, hs_ssp_clk,
 
 114         pck0, ck_1356meg, ck_1356megb,
 
 115         hisn_pwr_lo, hisn_pwr_hi, hisn_pwr_oe1, hisn_pwr_oe2, hisn_pwr_oe3,     hisn_pwr_oe4,
 
 117         hisn_ssp_frame, hisn_ssp_din, ssp_dout, hisn_ssp_clk,
 
 125 //   000 --  HF reader, transmitting to tag; modulation depth selectable
 
 126 //   001 --  HF reader, receiving from tag, correlating as it goes; frequency selectable
 
 127 //   010 --  HF simulated tag
 
 128 //   011 --  HF ISO14443-A
 
 129 //   111 --  everything off
 
 131 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);
 
 132 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);
 
 133 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);
 
 134 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);
 
 135 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);
 
 136 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);
 
 137 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);
 
 138 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);
 
 139 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);
 
 140 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);
 
 141 mux8 mux_dbg                    (major_mode, dbg,       ht_dbg,       hrxc_dbg,       hs_dbg,       hisn_dbg,       1'b0, 1'b0, 1'b0, 1'b0);
 
 143 // In all modes, let the ADC's outputs be enabled.
 
 144 assign adc_noe = 1'b0;