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tos-udp6-test#payload-stack-timediff

Simple code for sending and receiving a sequence of udp pakets.
Written for tinyOS in nesC and intended to run on Zolertia's Z1 board.

Under tinyOS the z1 generate a local link address in the form: fe80::212:6d4c:4f00:$NODE_ID The NODE_ID can be set only at build time by appending it to the install target install.$NODE_ID.
The hexfile is copied, patched, flashed and the copy is deleted aferwards.

build

UDPSendMon: make z1 blip install.1 bsl,ref,$BOARD_REF

UDPRecvMon: make z1 blip install.2 bsl,ref,$BOARD_REF

The unique BOARD_REF can be observed with motelist from the tinyos-tools.

Time measurement with TimeProbe:

Two time differences are measured.

  • On the sender side: The first time counter is sampled when invoking UDP.send() and the second when the packet is transmited into the radio chip.
  • On the receiver side: The first time counter is sampled right befor reading the arrived packet from the radio chip and the second when UDP.received offers the recieved payload.

A component has been implemented to provide a uniqe storage for timestamps (TMicro) including access methods to sample the timestamps and return the difference.
TimeProbe provides the intefaces StdControl and Get to make the commands start, stop and get accessible. TimeProbeControl.start() takes the first timestamp, TimeProbeControl.start() the second (if start has invoked before) and TimeProbeGet.get() returns the difference.

Important: tinyOS Millies have 2^10 ticks per second and Micros 2^20.

Code Locations

In UDPSendMon/CC2420TransmitP.nc :

570
571     if ( acquireSpiResource() == SUCCESS ) {
572       loadTXFIFO();
573       call TimeProbeControl.stop();
574     }

In UDPRecvMon/CC2420ReveiveP.nc :

212
213   /***************** InterruptFIFOP Events ****************/
214   async event void InterruptFIFOP.fired() {
215     call TimeProbeControl.start();
216     if ( m_state == S_STARTED ) {