3 files changed, 196 insertions(+), 2 deletions(-)

M tb/i2c/scl_generator_tb.vhd
M tb/i2c/tb_i2c_pkg.vhd
A tb/i2c/tb_i2c_slave_pkg.vhd

@@ 161,7 161,7 @@ begin  -- architecture tb
 
           stable_cannot_comply <= '0';
           wait_delay(1);
-          check_equal(cannot_comply, '1');
+          check_equal(cannot_comply, '1', "Wrong cannot comply");
         elsif run("falling_rising_scl_low") then
           req_falling;
           wait_delay(DELAY);


@@ 170,7 170,7 @@ begin  -- architecture tb
 
           stable_cannot_comply <= '0';
           wait_delay(DELAY);
-          check_equal(cannot_comply, '1');
+          check_equal(cannot_comply, '1', "Wrong cannot comply");
           check_equal(scl_enable, '0');
           wait_delay(DELAY);
           check_equal(scl_enable, '0');

@@ 41,6 41,24 @@ package tb_i2c_pkg is
     constant exp_data : in std_logic_vector(7 downto 0);
     signal rx_confirm_read : inout std_logic);
 
+  procedure wait_for_start_condition (
+    constant timeout : in time;
+    signal scl       : in std_logic;
+    signal sda       : in std_logic);
+
+  procedure wait_for_stop_condition (
+    constant timeout : in time;
+    signal scl       : in std_logic;
+    signal sda       : in std_logic);
+
+  procedure wait_for_scl_rise (
+    constant timeout : in time;
+    signal scl       : in std_logic);
+
+  procedure wait_for_scl_fall (
+    constant timeout : in time;
+    signal scl       : in std_logic);
+
 end package tb_i2c_pkg;
 
 package body tb_i2c_pkg is


@@ 128,4 146,42 @@ package body tb_i2c_pkg is
     rx_confirm_read <= '0';
   end procedure rx_read_data;
 
+  procedure wait_for_start_condition (
+    constant timeout : in time;
+    signal scl       : in std_logic;
+    signal sda       : in std_logic) is
+  begin
+    wait until falling_edge(sda) and scl = 'H' for timeout;
+    check(sda = '0' and scl = 'H', "Did not get start condition in time.");
+  end procedure wait_for_start_condition;
+
+  procedure wait_for_stop_condition (
+    constant timeout : in time;
+    signal scl       : in std_logic;
+    signal sda       : in std_logic) is
+  begin
+    wait until rising_edge(sda) and scl = 'H' for timeout;
+    check(sda = '1' and scl = 'H', "Did not get stop condition in time.");
+  end procedure wait_for_stop_condition;
+
+  procedure wait_for_scl_rise (
+    constant timeout : in time;
+    signal scl       : in std_logic) is
+  begin
+    wait until scl = 'H' for timeout;
+    check_equal(scl, 'H', "Did not get rising scl in time.");
+    wait until falling_edge(clk);
+  end procedure wait_for_scl_rise;
+
+
+  procedure wait_for_scl_fall (
+    constant timeout : in time;
+    signal scl       : in std_logic) is
+  begin
+    wait until scl = '0' for timeout;
+    check_equal(scl, '0', "Did not get falling scl in time.");
+    wait until falling_edge(clk);
+  end procedure wait_for_scl_fall;
+
+
 end package body tb_i2c_pkg;

@@ 0,0 1,138 @@
+library ieee;
+use ieee.std_logic_1164.all;
+
+library vunit_lib;
+-- use vunit_lib.check_pkg.all;
+context vunit_lib.vunit_context;
+
+use work.tb_pkg.all;
+use work.tb_i2c_pkg.all;
+
+package tb_i2c_slave_pkg is
+
+  procedure i2c_slave_check_start (
+    constant address : in std_logic_vector(6 downto 0);
+    constant rw : in std_logic;
+    constant timeout : in time;
+    signal scl : inout std_logic;
+    signal sda : inout std_logic;
+    constant ack : in std_logic := '1');
+
+  procedure i2c_slave_check_stop (
+    constant timeout : in time;
+    signal scl : inout std_logic;
+    signal sda : inout std_logic);
+
+  procedure i2c_slave_transmit (
+    constant data        : in    std_logic_vector(7 downto 0);
+    constant scl_timeout : in    time;
+    signal scl           : inout std_logic;
+    signal sda           : inout std_logic;
+    constant exp_ack     : in    std_logic := '1');
+
+  procedure i2c_slave_receive (
+    constant exp_data       : in    std_logic_vector(7 downto 0);
+    constant scl_timeout    : in    time;
+    signal scl              : inout std_logic;
+    signal sda              : inout std_logic;
+    constant ack            : in    std_logic := '1');
+
+end package tb_i2c_slave_pkg;
+
+package body tb_i2c_slave_pkg is
+
+  procedure i2c_slave_check_start (
+    constant address : in std_logic_vector(6 downto 0);
+    constant rw : in std_logic;
+    constant timeout : in time;
+    signal scl : inout std_logic;
+    signal sda : inout std_logic;
+    constant ack : in std_logic := '1') is
+    begin
+      wait_for_start_condition(timeout, scl, sda);
+      i2c_slave_receive(address & rw, timeout, scl, sda, ack);
+    end procedure i2c_slave_check_start;
+
+  procedure i2c_slave_check_stop (
+    constant timeout : in time;
+    signal scl : inout std_logic;
+    signal sda : inout std_logic) is
+  begin
+    wait_for_stop_condition(timeout, scl, sda);
+  end procedure i2c_slave_check_stop;
+
+  procedure i2c_slave_transmit (
+    constant data        : in    std_logic_vector(7 downto 0);
+    constant scl_timeout : in    time;
+    signal scl           : inout std_logic;
+    signal sda           : inout std_logic;
+    constant exp_ack     : in    std_logic := '1') is
+
+  begin  -- procedure transmit
+    report "Start slave transmit";
+    if scl = 'H' then
+        wait_for_scl_fall(scl_timeout, scl);
+    end if;
+
+    -- data
+    for i in 7 downto 0 loop
+    report "Data " & integer'image(i) & " scl is: " & std_logic'image(scl);
+      wait until falling_edge(clk);
+      sda <= '0' when data(i) = '0' else 'Z';
+      wait_for_scl_rise(scl_timeout, scl);
+      wait_for_scl_fall(scl_timeout, scl);
+    end loop;  -- i
+
+    wait until falling_edge(clk);
+    sda <= 'Z';
+    wait_for_scl_rise(scl_timeout, scl);
+
+    report "Ack slave transmit";
+    if exp_ack = '1' then
+      check_equal(sda, '0', "No acknowledge");
+    elsif exp_ack = '0' then
+      check_equal(sda, 'H', "There was acknowledge even though there shouldn't have been");
+    end if;
+
+    -- TODO consider removing this?
+    wait_for_scl_fall(scl_timeout, scl);
+    wait until falling_edge(clk);
+    sda <= 'Z';
+  end procedure i2c_slave_transmit;
+
+  procedure i2c_slave_receive (
+    constant exp_data       : in    std_logic_vector(7 downto 0);
+    constant scl_timeout    : in    time;
+    signal scl              : inout std_logic;
+    signal sda              : inout std_logic;
+    constant ack            : in    std_logic := '1') is
+
+  begin  -- procedure transmit
+    if scl = 'H' then
+      wait_for_scl_fall(scl_timeout, scl);
+    end if;
+
+    sda <= 'Z';
+
+    -- data
+    for i in 7 downto 0 loop
+      wait_for_scl_rise(scl_timeout, scl);
+      if exp_data(i) = '1' then
+        check(sda = '1' or sda = 'H', result("Received data (sda) not as expected."));
+      else
+        check(sda = '0' or sda = 'L', result("Received data (sda) not as expected."));
+      end if;
+      wait_for_scl_fall(scl_timeout, scl);
+    end loop;  -- i
+
+    if ack = '1' then
+      sda <= '0';
+    end if;
+
+    wait_for_scl_rise(scl_timeout, scl);
+    wait_for_scl_fall(scl_timeout, scl);
+
+    sda <= 'Z';
+  end procedure i2c_slave_receive;
+
+end package body tb_i2c_slave_pkg;