Limit hexsamples to just the amount of requested samples

[proxmark3-svn] / fpga / lo_simulate.v

//-----------------------------------------------------------------------------\r
// The way that we connect things in low-frequency simulation mode. In this\r
// case just pass everything through to the ARM, which can bit-bang this\r
// (because it is so slow).\r
//\r
// Jonathan Westhues, April 2006\r
//-----------------------------------------------------------------------------\r
\r
module lo_simulate(\r
    pck0, ck_1356meg, ck_1356megb,\r
    pwr_lo, pwr_hi, pwr_oe1, pwr_oe2, pwr_oe3, pwr_oe4,\r
    adc_d, adc_clk,\r
    ssp_frame, ssp_din, ssp_dout, ssp_clk,\r
    cross_hi, cross_lo,\r
    dbg,
	 divisor\r
);\r
    input pck0, ck_1356meg, ck_1356megb;\r
    output pwr_lo, pwr_hi, pwr_oe1, pwr_oe2, pwr_oe3, pwr_oe4;\r
    input [7:0] adc_d;\r
    output adc_clk;\r
    input ssp_dout;\r
    output ssp_frame, ssp_din, ssp_clk;\r
    input cross_hi, cross_lo;\r
    output dbg;
	 input [7:0] divisor;\r
\r
// No logic, straight through.\r
assign pwr_oe3 = 1'b0;\r
assign pwr_oe1 = ssp_dout;\r
assign pwr_oe2 = ssp_dout;\r
assign pwr_oe4 = ssp_dout;\r
assign ssp_clk = cross_lo;\r
assign pwr_lo = 1'b0;\r
assign pwr_hi = 1'b0;\r
assign dbg = ssp_frame;\r

// Divide the clock to be used for the ADC
reg [7:0] pck_divider;
reg clk_state;
\r
always @(posedge pck0)\r
begin\r
	if(pck_divider == divisor[7:0])\r
		begin\r
			pck_divider <= 8'd0;
			clk_state = !clk_state;\r
		end\r
	else\r
	begin\r
		pck_divider <= pck_divider + 1;\r
	end\r
end\r

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)\r
begin\r
	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;
\r
endmodule\r