diff --git a/src/vhdl/keypad_i2c.vhdl b/src/vhdl/keypad_i2c.vhdl
index 73cfa61ac..13ba4c6dd 100644
--- a/src/vhdl/keypad_i2c.vhdl
+++ b/src/vhdl/keypad_i2c.vhdl
@@ -688,7 +688,7 @@ begin
           -- Write to a register, if a request is pending:
           -- First, write the address and register number.
           if last_busy_count /= busy_count then
-            report "Writing to register $" & to_hstring(write_reg);
+            report "Writing to register $" & to_hexstring(write_reg);
           end if;
           i2c1_rw <= '0';
           command_en <= '1';
@@ -699,7 +699,7 @@ begin
         when max_state+2 =>
           -- Second, write the actual value into the register
           if last_busy_count /= busy_count then
-            report "Writing value $" & to_hstring(write_val) & " to register";
+            report "Writing value $" & to_hexstring(write_val) & " to register";
           end if;
           -- Make sure we send a STOP before the next command starts
           -- NOTE: This is done above in the incrementer for busy_count
diff --git a/src/vhdl/tb_keypad_i2c.vhdl b/src/vhdl/tb_keypad_i2c.vhdl
new file mode 100644
index 000000000..9ea6b9aaa
--- /dev/null
+++ b/src/vhdl/tb_keypad_i2c.vhdl
@@ -0,0 +1,95 @@
+library ieee;
+use ieee.std_logic_1164.all;
+use ieee.numeric_std.all;
+use Std.TextIO.all;
+use work.debugtools.all;
+use work.cputypes.all;
+
+library vunit_lib;
+context vunit_lib.vunit_context;
+
+entity tb_keypad_i2c is
+  generic (runner_cfg : string);
+end entity;
+
+architecture test_arch of tb_keypad_i2c is
+
+  signal clock41 : std_logic := '0';
+
+  signal sda : std_logic;
+  signal scl : std_logic;
+
+  signal cs : std_logic := '0';
+  signal fastio_read : std_logic := '0';
+  signal fastio_write : std_logic := '0';
+  signal fastio_rdata : unsigned(7 downto 0);
+  signal fastio_wdata : unsigned(7 downto 0) := to_unsigned(0,8);
+  signal fastio_addr : unsigned(19 downto 0) := x"00000";
+  
+  signal port0 : unsigned(7 downto 0) := x"00";
+  signal port1 : unsigned(7 downto 0) := x"50";
+
+  signal reset_high : std_logic;
+  
+begin
+
+  pca0: entity work.pca9555
+    generic map ( clock_frequency => 40_500_000,
+                  address => b"0100000"
+                  )
+    port map ( clock => clock41,
+               reset => reset_high,
+               scl => scl,
+               sda => sda,
+               port0 => port0,
+               port1 => port1);
+
+
+  unit0: entity work.keypad_i2c
+    generic map (clock_frequency => 40_500_000 )
+    port map ( clock => clock41,
+               sda => sda,
+               scl => scl,
+
+               cs => cs,
+               fastio_read => fastio_read,
+               fastio_write => fastio_write,
+               fastio_rdata => fastio_rdata,
+               fastio_wdata => fastio_wdata,
+               fastio_addr => fastio_addr
+               );
+
+  sda <= 'H';
+  scl <= 'H';
+  
+  main : process
+
+    variable v : unsigned(15 downto 0);
+
+    procedure clock_tick is
+    begin
+      clock41 <= not clock41;
+      wait for 12 ns;
+
+    end procedure;
+
+  begin
+    test_runner_setup(runner, runner_cfg);
+
+    while test_suite loop
+
+      if run("I2C runs") then
+
+        reset_high <= '1'; clock_tick;clock_tick;clock_tick;clock_tick;
+        reset_high <= '0'; clock_tick;clock_tick;clock_tick;clock_tick;
+        
+        for i in 1 to 100000 loop
+          clock_tick;
+        end loop;
+
+      end if;
+    end loop;
+    test_runner_cleanup(runner);
+  end process;
+
+end architecture;
diff --git a/test_keypad_i2c.py b/test_keypad_i2c.py
new file mode 100755
index 000000000..78af30e6d
--- /dev/null
+++ b/test_keypad_i2c.py
@@ -0,0 +1,26 @@
+#!/bin/env python3
+
+from vunit import VUnit
+
+# Create VUnit instance by parsing command line arguments
+vu = VUnit.from_argv()
+
+# Create library 'lib'
+lib = vu.add_library("lib")
+
+lib.add_source_files("src/vhdl/tb_keypad_i2c.vhdl");
+lib.add_source_files("src/vhdl/keypad_i2c.vhdl");
+lib.add_source_files("src/vhdl/i2c_master.vhdl");
+lib.add_source_files("src/vhdl/i2c_slave_frank_buss.vhdl");
+lib.add_source_files("src/vhdl/pca9555.vhdl");
+lib.add_source_files("src/vhdl/debounce.vhdl");
+lib.add_source_files("src/vhdl/debugtools.vhdl")
+lib.add_source_files("src/vhdl/cputypes.vhdl")
+
+vu.set_compile_option("ghdl.a_flags", ["-frelaxed-rules"])
+vu.set_compile_option("ghdl.flags", ["-frelaxed-rules"])
+vu.set_sim_option("ghdl.elab_flags", ["-frelaxed-rules"])
+vu.set_sim_option("ghdl.sim_flags", ["--ieee-asserts=disable"])
+
+# Run vunit function
+vu.main()