title: Convert char* to unsigned char arduino
body: <p>I have a char array </p>
  
  <p><code>char data[] = "0123456789012345"; //16 chars == 16 bytes</code></p>
  
  <p>I want to send this data thru BLE shield using this method</p>
  
  <p><code>void ble_write(unsigned char data);</code></p>
  
  <p>This is my code in Arduino</p>
  
  <p><code>ble_write(data);</code></p>
  
  <p>I am getting this error <code>invalid conversion from 'char*' to 'unsigned char' [-fpermissive]</code></p>
  
  <p>What can I do to convert char* to unsigned char?</p>