proxmark3/fpga/lo_simulate.v
2023-05-30 19:47:27 +02:00

102 lines
2.5 KiB
Verilog

//-----------------------------------------------------------------------------
// Copyright (C) Proxmark3 contributors. See AUTHORS.md for details.
//
// This program is free software: you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU General Public License for more details.
//
// See LICENSE.txt for the text of the license.
//-----------------------------------------------------------------------------
//
// The way that we connect things in low-frequency simulation mode. In this
// case just pass everything through to the ARM, which can bit-bang this
// (because it is so slow).
//
// Jonathan Westhues, April 2006
//-----------------------------------------------------------------------------
module lo_simulate(
input pck0,
input ck_1356meg,
input ck_1356megb,
input [7:0] adc_d,
input [7:0] divisor,
input cross_hi,
input cross_lo,
input ssp_dout,
output ssp_din,
output ssp_frame,
output ssp_clk,
output adc_clk,
output pwr_lo,
output pwr_hi,
output pwr_oe1,
output pwr_oe2,
output pwr_oe3,
output pwr_oe4,
output debug
);
// No logic, straight through.
assign pwr_oe3 = 1'b0;
assign pwr_oe1 = ssp_dout;
assign pwr_oe2 = ssp_dout;
assign pwr_oe4 = ssp_dout;
assign ssp_clk = cross_lo;
assign pwr_lo = 1'b0;
assign pwr_hi = 1'b0;
assign debug = ssp_frame;
// Divide the clock to be used for the ADC
reg [7:0] pck_divider;
reg clk_state;
always @(posedge pck0)
begin
if(pck_divider == divisor[7:0])
begin
pck_divider <= 8'd0;
clk_state = !clk_state;
end
else
begin
pck_divider <= pck_divider + 1;
end
end
assign adc_clk = ~clk_state;
// Toggle the output with hysteresis
// Set to high if the ADC value is above 200
// Set to low if the ADC value is below 64
reg is_high;
reg is_low;
reg output_state;
always @(posedge pck0)
begin
if((pck_divider == 8'd7) && !clk_state) begin
is_high = (adc_d >= 8'd191);
is_low = (adc_d <= 8'd64);
end
end
always @(posedge is_high or posedge is_low)
begin
if(is_high)
output_state <= 1'd1;
else if(is_low)
output_state <= 1'd0;
end
assign ssp_frame = output_state;
endmodule