-<p>It also provides interfaces for configuring the serial port. <em>NOTE:
-These are not codified yet, and so working out the UART HIL seems like
-a good idea.</em></p>
+<p>Alternatively, <tt class="docutils literal"><span class="pre">UartC</span></tt> may provide the UartStream multi-byte level
+interface. See the Low-Level I/O TEP [<a class="reference" href="#tep117">TEP117</a>] for details.</p>
+<p>Additionally, UartC provides a split-phase interface to signal when
+the UART is idle. There are situations (such as when powering down the
+usart, when switching from TX to RX on a radio with a UART data line,
+etc.) when we need explicit information that the data sent over the
+UART has actually been transmitted in full. The problem is that on
+MCUs that double-buffer UART communication (such as the msp430), a
+putDone event signifies that the UART is ready to accept another byte,
+but NOT that the UART is idle.</p>
+<pre class="literal-block">
+interface SerialFlush {
+ command void flush();
+ event void flushDone();
+}
+</pre>
+<p>It may provide additional interfaces for configuring the serial
+port. This TEP does not consider this topic.</p>