List to show time - half hour interval

I have a PHP page to show a select list of time in half an hour interval.

For now I selected it manually
<option value="oneThirty">1:30AM</option>
<option value="two">2AM</option>
...

Is there way I can do it using loop in PHP with half hour interval and how?

Thanks

 

maybe something like this:

<?
 for($hour=0;$hour<24;$hour++){
  if($hour<12){ $ampm = "AM"; } else { $ampm = "PM"; }
  $selTime .= "<option value=\"".sprintf("%02d",$hour).":00$ampm\">".sprintf("%02d",$hour).":00$ampm</option>";
  $selTime .= "<option value=\"".sprintf("%02d",$hour).":30$ampm\">".sprintf("%02d",$hour).":30$ampm</option>";
 }
?>

<select>
 <?=$selTime?>
</select>

PHP:

 

Thanks, that is helpful.