35 lines
1.0 KiB
Coq
35 lines
1.0 KiB
Coq
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// look in pins.pcf for all the pin names on the TinyFPGA BX board
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module top (
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input CLK, // 16MHz clock
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output LED, // User/boot LED next to power LED
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output USBPU // USB pull-up resistor
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);
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// drive USB pull-up resistor to '0' to disable USB
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assign USBPU = 0;
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////////
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// make a simple blink circuit
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////////
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// keep track of time and location in blink_pattern
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reg [20:0] clock_counter = 21'b000000000000000000000;
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reg [3:0] blink_counter = 4'b0000;
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// pattern that will be flashed over the LED over time
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wire [9:0] blink_pattern = 10'b1010000000;
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// increment the blink_counter every clock
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always @(posedge CLK) begin
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clock_counter <= clock_counter + 1;
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if (clock_counter == 21'b110000110101000000000) begin
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blink_counter <= blink_counter + 1;
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clock_counter <= 0;
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end
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if (blink_counter == 4'b1011) blink_counter <= 0;
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end
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// light up the LED according to the pattern
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assign LED = blink_pattern[blink_counter];
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endmodule
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