examples: reorganize into examples/basic and examples/board.

examples/board/blinky.py

@@ -0,0 +1,21 @@
+from nmigen import *
+from nmigen.vendor.board.ice40_hx1k_blink_evn import *
+
+
+class Blinky(Elaboratable):
+    def elaborate(self, platform):
+        clk3p3   = platform.request("clk3p3")
+        user_led = platform.request("user_led", 0)
+        counter  = Signal(20)
+
+        m = Module()
+        m.domains.sync = ClockDomain()
+        m.d.comb += ClockSignal().eq(clk3p3.i)
+        m.d.sync += counter.eq(counter + 1)
+        m.d.comb += user_led.o.eq(counter[-1])
+        return m
+
+
+if __name__ == "__main__":
+    platform = ICE40HX1KBlinkEVNPlatform()
+    platform.build(Blinky(), do_program=True)