Improve examples for Lattice iCEstick

- move "leds" examples to subdirectory
- add Makefile
- add *.json files to .gitignore
- adjust README.md and fix some typos

1 files changed, 38 insertions, 0 deletions

diff --git a/examples/icestick/leds/rotate3.vhdl b/examples/icestick/leds/rotate3.vhdl
new file mode 100644
index 0000000..213512f
--- /dev/null
+++ b/examples/icestick/leds/rotate3.vhdl
@@ -0,0 +1,38 @@
+architecture rotate3 of leds is
+  signal clk_4hz: std_logic;
+begin
+  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" =>
+          (led1, led2, led3, led4, led5) <= unsigned'("10001");
+        when "01" =>
+          (led1, led2, led3, led4, led5) <= unsigned'("01000");
+        when "10" =>
+          (led1, led2, led3, led4, led5) <= unsigned'("00101");
+        when "11" =>
+          (led1, led2, led3, led4, led5) <= unsigned'("00010");
+        when others =>
+          null;
+      end case;
+      count := count + 1;
+    end if;
+  end process;
+end rotate3;