//$Id: ReceiveBytePacket.nc,v 1.4 2006/12/12 18:23:31 vlahan Exp $

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 * All rights reserved.
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 * IN NO EVENT SHALL THE UNIVERSITY OF CALIFORNIA BE LIABLE TO ANY PARTY FOR
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/**
 * This is the data interface that a serial protocol provides and
 * a serial dispatcher uses. The dispatcher expects the following pattern
 * of calls: ((startPacket)+ (byteReceived)* (endPacket)+)*
 * It should ignore any signals that do not follow this pattern.
 * The interface is used to separate the state machine of the wire protocol
 * from the complexities of dispatch.
 *
 * @author Philip Levis
 * @author Ben Greenstein
 * @date August 7 2005
 *
 */

interface ReceiveBytePacket {

  
  /**
   * Signals the upper layer to indicate that reception of a frame has begun.
   * Used by the upper layer to prepare for packet reception. If the upper
   * layer does not want to receive a packet (or isn't ready) it may
   * return a non-SUCCESS code  such as EBUSY to the lower layer to discard
   * the frame. The underlying layer may signal endPacket in response to
   * such a discard request.
   * @return Returns an error_t code indicating whether the
   * dispatcher would like to receive a packet (SUCCESS), or not
   * perhaps because it isn't ready (EBUSY).
   */
  async event error_t startPacket();

  /**
   * Signals the upper layer that a byte of the encapsulated packet has been
   * received. Passes this byte as a parameter to the function.
   * @param data A byte of the encapsulated packet that has been received.
   */
  async event void byteReceived(uint8_t data);
  /**
   * Signalled to indicate that a packet encapsulated withing a serial
   * frame has been received. SUCCESS should be passed by the lower layer
   * following verification that the packet has been received correctly.
   * A value of error_t indicating an error should be passed when the lower
   * layer's verification test fails or when the lower layer loses sync.
   * @param result An error_t code indicating whether the framer has
   * passed all bytes of an encapsulated packet it receives from
   * serial to the dispatcher (SUCCESS) or not (FAIL).
   */
  async event void endPacket(error_t result);
}