migrate from Travis to GHA and rework examples (#78)

* migrate from Travis to GHA

* rework examples

1 files changed, 41 insertions, 0 deletions

diff --git a/examples/icestick/rotate4.vhdl b/examples/icestick/rotate4.vhdl
new file mode 100644
index 0000000..e89aaa5
--- /dev/null
+++ b/examples/icestick/rotate4.vhdl
@@ -0,0 +1,41 @@
+architecture rotate4 of leds is
+  signal clk_4hz: std_logic;
+  signal leds : std_ulogic_vector (1 to 5);
+begin
+  (led1, led2, led3, led4, led5) <= leds;
+
+  process (clk)
+    --  3_000_000 is 0x2dc6c0
+    variable counter : unsigned (23 downto 0);
+  begin
+    if rising_edge(clk) then
+      if counter = 2_999_999 then
+        counter := x"000000";
+        clk_4hz <= '1';
+      else
+        counter := counter + 1;
+        clk_4hz <= '0';
+      end if;
+    end if;
+  end process;
+
+  process (clk)
+    variable count : unsigned (1 downto 0);
+  begin
+    if rising_edge(clk) and clk_4hz = '1' then
+      case count is
+        when "00" =>
+          leds <= "10001";
+        when "01" =>
+          leds <= "01000";
+        when "10" =>
+          leds <= "00101";
+        when "11" =>
+          leds <= "00010";
+        when others =>
+          null;
+      end case;
+      count := count + 1;
+    end if;
+  end process;
+end rotate4;