proxmark3/fpga/lo_simulate.v
bushing ba06a4b694 setting svn:eol-style=native on files, part 3
(should be done now, sorry)
2010-02-22 19:29:05 +00:00

84 lines
1.8 KiB
Verilog

//-----------------------------------------------------------------------------
// 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(
pck0, ck_1356meg, ck_1356megb,
pwr_lo, pwr_hi, pwr_oe1, pwr_oe2, pwr_oe3, pwr_oe4,
adc_d, adc_clk,
ssp_frame, ssp_din, ssp_dout, ssp_clk,
cross_hi, cross_lo,
dbg,
divisor
);
input pck0, ck_1356meg, ck_1356megb;
output pwr_lo, pwr_hi, pwr_oe1, pwr_oe2, pwr_oe3, pwr_oe4;
input [7:0] adc_d;
output adc_clk;
input ssp_dout;
output ssp_frame, ssp_din, ssp_clk;
input cross_hi, cross_lo;
output dbg;
input [7:0] divisor;
// 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 dbg = 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'd200);
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