Interface: tos.lib.serial.SendBytePacket

interface SendBytePacket

This is an interface that a serial framing protocol provides and a serial dispatcher uses. The call sequence should be as follows: The dispatcher should call startSend, specifying the first byte to send. The framing protocol can then signal as many nextBytes as it wants/needs, to spool in the bytes. It continues to do so until it receives a sendComplete call, which will almost certainly happen within a nextByte signal (i.e., re-entrant to the framing protocol). This allows the framing protocol to buffer as many bytes as it needs to to meet timing requirements, jitter, etc.

Author:: Philip Levis; Ben Greenstein
Date:: August 7 2005

Commands

command error_t completeSend() The dispatcher must indicate when the end-of-packet has been reached and does so by calling completeSend.

command error_t startSend(uint8_t first_byte) The dispatcher may initiate a serial transmission by calling this function and passing the first byte to be transmitted.

Events

event uint8_t nextByte() Used by the framer to request the next byte to transmit.

event void sendCompleted(error_t error) The framer signals sendCompleted to indicate that it is done transmitting a packet on the dispatcher's behalf.

Commands - Details

completeSend

command error_t completeSend()

The dispatcher must indicate when the end-of-packet has been reached and does so by calling completeSend. The function may be called from within the implementation of a nextByte event.

Returns:: Returns an error_t code indicating whether the framer accepts this notification (SUCCESS) or not (FAIL).

startSend

command error_t startSend(uint8_t first_byte)

The dispatcher may initiate a serial transmission by calling this function and passing the first byte to be transmitted.

Parameters:: first_byte - The first byte to be transmitted.
Returns:: Returns an error_t code indicating either that the framer has the resources available to transmit the frame (SUCCESS) or not (EBUSY).

Events - Details

nextByte

event uint8_t nextByte()

Used by the framer to request the next byte to transmit. The framer may allocate a buffer to pre-spool some or all of a packet; or it may request and transmit a byte at a time. If there are no more bytes to send, the dispatcher must call completeSend before returning from this function.

Returns:: The dispatcher must return the next byte to transmit

sendCompleted

event void sendCompleted(error_t error)

The framer signals sendCompleted to indicate that it is done transmitting a packet on the dispatcher's behalf. A non-SUCCESS error_t code indicates that there was a problem in transmission.

Parameters:: error - The framer indicates whether it has successfully accepted the entirety of the packet from the dispatcher (SUCCESS) or not (FAIL).