Initial

.gitignore

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+build

README.md

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+# Verilog
+
+This is all work in progress.
+
+[Post](https://mcmayer.net/first-steps-with-the-icestorm-toolchain/)
+[Video Series](https://www.youtube.com/playlist?list=PLEBQazB0HUyT1WmMONxRZn9NmQ_9CIKhb)
+
+## Dependencies
+
+```bash
+sudo dnf install yosys icestorm arachne-pnr
+```

blinky.pcf

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+set_io clk_in 21  
+set_io led_green_out 95  
+set_io led_red[0] 96  
+set_io led_red[1] 97  
+set_io led_red[2] 98  
+set_io led_red[3] 99  

blinky.v

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+// blinky.v
+// Blink the green LED with frequency 12e6/2^24 = 0.7Hz approx.
+module top (clk_in, led_green_out);  
+    input clk_in;
+    output led_green_out;
+
+
+    reg [23:0] counter;
+    assign led_green_out = counter[23];
+    assign led_red[3:0] = 4'b0;
+
+    always @ (posedge clk_in) begin
+        counter <= counter + 1;
+    end
+
+endmodule  

makefile

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+all: build/blinky.bin
+
+build/blinky.bin: build/blinky.asc  
+	icepack $< $@
+
+build/blinky.asc: blinky.pcf build/blinky.blif  
+	arachne-pnr -d 1k -P tq144 -o $@ -p $^
+
+build/blinky.blif: blinky.v  
+	mkdir -p build
+	yosys -p "synth_ice40 -top top -blif $@" $^
+
+prog: build/blinky.bin  
+	iceprog build/blinky.bin
+
+clean:  
+	rm build/*
+
+.PHONY: prog clean
+