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minor code cleanup
[proxmark3-svn] / fpga / lo_simulate.v
1 //-----------------------------------------------------------------------------
2 // The way that we connect things in low-frequency simulation mode. In this
3 // case just pass everything through to the ARM, which can bit-bang this
4 // (because it is so slow).
5 //
6 // Jonathan Westhues, April 2006
7 //-----------------------------------------------------------------------------
8
9 module lo_simulate(
10 pck0, ck_1356meg, ck_1356megb,
11 pwr_lo, pwr_hi, pwr_oe1, pwr_oe2, pwr_oe3, pwr_oe4,
12 adc_d, adc_clk,
13 ssp_frame, ssp_din, ssp_dout, ssp_clk,
14 cross_hi, cross_lo,
15 dbg,
16 divisor
17 );
18 input pck0, ck_1356meg, ck_1356megb;
19 output pwr_lo, pwr_hi, pwr_oe1, pwr_oe2, pwr_oe3, pwr_oe4;
20 input [7:0] adc_d;
21 output adc_clk;
22 input ssp_dout;
23 output ssp_frame, ssp_din, ssp_clk;
24 input cross_hi, cross_lo;
25 output dbg;
26 input [7:0] divisor;
27
28 // No logic, straight through.
29 assign pwr_oe3 = 1'b0;
30 assign pwr_oe1 = ssp_dout;
31 assign pwr_oe2 = ssp_dout;
32 assign pwr_oe4 = ssp_dout;
33 assign ssp_clk = cross_lo;
34 assign pwr_lo = 1'b0;
35 assign pwr_hi = 1'b0;
36 assign dbg = ssp_frame;
37
38 // Divide the clock to be used for the ADC
39 reg [7:0] pck_divider;
40 reg clk_state;
41
42 always @(posedge pck0)
43 begin
44 if(pck_divider == divisor[7:0])
45 begin
46 pck_divider <= 8'd0;
47 clk_state = !clk_state;
48 end
49 else
50 begin
51 pck_divider <= pck_divider + 1;
52 end
53 end
54
55 assign adc_clk = ~clk_state;
56
57 // Toggle the output with hysteresis
58 // Set to high if the ADC value is above 200
59 // Set to low if the ADC value is below 64
60 reg is_high;
61 reg is_low;
62 reg output_state;
63
64 always @(posedge pck0)
65 begin
66 if((pck_divider == 8'd7) && !clk_state) begin
67 is_high = (adc_d >= 8'd200);
68 is_low = (adc_d <= 8'd64);
69 end
70 end
71
72 always @(posedge is_high or posedge is_low)
73 begin
74 if(is_high)
75 output_state <= 1'd1;
76 else if(is_low)
77 output_state <= 1'd0;
78 end
79
80 assign ssp_frame = output_state;
81
82 endmodule
83
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