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ba06a4b6 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
9module 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,
802a3616 15 dbg,
ba06a4b6 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;
802a3616 25 output dbg;
ba06a4b6 26 input [7:0] divisor;
27
28// No logic, straight through.
29assign pwr_oe3 = 1'b0;
30assign pwr_oe1 = ssp_dout;
31assign pwr_oe2 = ssp_dout;
32assign pwr_oe4 = ssp_dout;
33assign ssp_clk = cross_lo;
34assign pwr_lo = 1'b0;
35assign pwr_hi = 1'b0;
36assign dbg = ssp_frame;
802a3616 37
38// Divide the clock to be used for the ADC
39reg [7:0] pck_divider;
40reg clk_state;
ba06a4b6 41
42always @(posedge pck0)
43begin
44 if(pck_divider == divisor[7:0])
45 begin
802a3616 46 pck_divider <= 8'd0;
ba06a4b6 47 clk_state = !clk_state;
48 end
49 else
50 begin
51 pck_divider <= pck_divider + 1;
52 end
53end
802a3616 54
55assign 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
60reg is_high;
61reg is_low;
62reg output_state;
63
ba06a4b6 64always @(posedge pck0)
65begin
802a3616 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
70end
71
72always @(posedge is_high or posedge is_low)
73begin
74 if(is_high)
75 output_state <= 1'd1;
76 else if(is_low)
77 output_state <= 1'd0;
78end
79
80assign ssp_frame = output_state;
ba06a4b6 81
82endmodule
83
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