title: convert integer to std_logic
body: <p>Suppose you have a loop</p>
  
  <pre><code>for i in 1 downto 0 loop
      for j in 1 downto 0 loop
          tS0 &lt;= i;
  </code></pre>
  
  <p>But I need to convert the integer (which is natural) to std_logic. <strong>tS0</strong> is declared as std_logic. I am only doing it one bit (0 or 1). That is, my <strong>i</strong> and <strong>j</strong> can only represent the value {0,1}. </p>
  
  <p>I think I am heading to the wrong approach here. Can someone please tell me what should I do instead?  </p>
  
  <p>I don't think std_logic has to_unsigned method. i tried letting <strong>tS0</strong> to be a vector (1 down to 0), and assigned like <strong>tS0(0) &lt;= i</strong>, and etc. But it still didn't work out.</p>
  
  <p>Thank you very much!</p>