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AVR Motes in Cooja

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Benoît Thébaudeau edited this page Sep 23, 2019 · 6 revisions

Cooja uses the Avrora simulator for AVR motes. Platforms currently available are:

  • MicaZ (ATmega128L + CC2420 radio)
  • Raven (ATmega1284p + AT86RF230 radio, using the RF231 emulator)
  • avr-atmega128rfa1 (the bare chip, in Cooja the platform is named RFA1)
The MicaZ platform may be usable with the existing avrora-small.jar library but extensions for extra timers and interrupts are needed for the others. Until the source is stable enough for a new library you will need to replace the cooja folder in /tools with the version in http://github.com/fros4943/cooja-avrora-patch-wip.git. This version has java 1.7 jar libraries so instant contiki may require upgrading from java 1.6.

Cooja currently simulates radio transmissions between motes of the same type as 802.15.4 byte streams (preamble, start of frame delimiter, data, and checksum), but complete packets are used when motes are of different type. However it is possible to have the avr platforms communicate among themselves at the stream level, and with sky radios as well. This requires changes in the AbstractRadioMedium, Radio802154, and CustomDataRadio java files which are included in the above repository.

For simplicity this example uses UDP-ipv6 server/client motes with no RPL or radio duty cycling. Prebuilt targets for all the platforms are available in the /tools/cooja/examples/uip_client_server_binaries folder.

See An Introduction to Cooja for general information about running Cooja. 

 cd /tools/cooja
 ant clean
 ant run

will compile all the sources and launch the simulation window. Choose File->New simulation and then Mote Types->Create mote type->Raven mote type. Browse to the udp-server.avr-raven file, open, create, create and add. The server must be node 1 as all the clients will use a fixed aaaa::212:7401:1:101 address for it.

Now add a client: Mote Types->Create mote type->Raven mote type and open udp-client.avr-raven. Two circles will have appeared in the Visualizer window at random locations. They may be too far apart for radio communication, so drag one close to the other!!!

Start the simulation and the boot messages will appear. The motes are given random startup times; in this case the client starts before the server. The output from UART0 is shown in the log window 

 244	ID:2	
 247	ID:2	Checking MCUSR...
 251	ID:2	CLOCK_SECOND 128
 255	ID:2	RTIMER_ARCH_SECOND 7812
 258	ID:2	F_CPU 8000000
 259	ID:2	
 269	ID:2	*******Booting Contiki-2.5-release-454-g88eafcf*******
 275	ID:2	rng issues 171
 278	ID:2	Initial node_id 2
 284	ID:2	EUI-64 MAC: 0-12-74-2-0-2-2-2
 297	ID:2	nullmac sicslowmac, channel 26 , check rate 128 Hz tx power 0
 304	ID:2	UDP client process started
 312	ID:2	Client IPv6 addresses: aaaa::212:7402:2:202
 316	ID:2	fe80::212:7402:2:202
 332	ID:2	Created a connection with the server aaaa::212:7401:1:101 local/remote port 3001/3000
 333	ID:2	Online	
 390	ID:1	
 393	ID:1	Checking MCUSR...
 397	ID:1	CLOCK_SECOND 128
 401	ID:1	RTIMER_ARCH_SECOND 7812
 404	ID:1	F_CPU 8000000
 405	ID:1	
 415	ID:1	*******Booting Contiki-2.5-release-454-g88eafcf*******
 421	ID:1	rng issues 171
 424	ID:1	Initial node_id 1
 430	ID:1	EUI-64 MAC: 0-12-74-1-0-1-1-1
 442	ID:1	nullmac sicslowmac, channel 26 , check rate 128 Hz tx power 0
 448	ID:1	UDP server started
 457	ID:1	Server IPv6 addresses: aaaa::212:7401:1:101
 460	ID:1	fe80::212:7401:1:101
 462	ID:1	Online
 2344	ID:2	Addresses [4 max]
 2348	ID:2	aaaa::212:7402:2:202
 2352	ID:2	fe80::212:7402:2:202
 2353	ID:2	
 2356	ID:2	Neighbors [20 max]
 2358	ID:2	  <none>
 2361	ID:2	Routes [20 max]
 2363	ID:2	  <none>
 2365	ID:2	---------
 2490	ID:1	Addresses [4 max]
 2494	ID:1	aaaa::212:7401:1:101
 2498	ID:1	fe80::212:7401:1:101
 2499	ID:1	
 2502	ID:1	Neighbors [20 max]
 2504	ID:1	  <none>
 2507	ID:1	Routes [20 max]
 2509	ID:1	  <none>
 2511	ID:1	---------
 3396	ID:2	Never-used stack > 4830 bytes
 3542	ID:1	Never-used stack > 4840 bytes
 16067	ID:2	Client sending to: aaaa::212:7401:1:101 (msg: Hello 1 from the client)
 16096	ID:1	Server received: 'Hello 1 from the client' from aaaa::212:7402:2:202
 16106	ID:1	Responding with message: Hello from the server! (1)
 16122	ID:2	Response from the server: 'Hello from the server! (1)'

Pause the simulation and open the radio logger plugin, right-click on it, and enable 6LoWPAN analyzer. Start simulation and you can see the packets being exchanged:
files/udp-client-server.png

Check out the various interfaces shown when you right-click on a mote. Three LED's are enabled, connected to PORTD but that is easily changed in the /avrora/sim/platform/Raven.java file. As you can see, the hardware pins can be referenced either symbolically or by actual pin number: 

        ledGroup = new LED.LEDGroup(sim, new LED[] { yellow, green, red });
        addDevice("leds", ledGroup);
 
        AtmelMicrocontroller amcu = (AtmelMicrocontroller)mcu;
        if (true) {
            mcu.getPin("PD5").connectOutput(yellow);
            mcu.getPin("PD6").connectOutput(green);
            mcu.getPin("PD7").connectOutput(red);
        }
        // install the new AT86RF230 radio. Actually an AT86RF231.
        AT86RF231Radio radio = new AT86RF231Radio(mcu, MAIN_HZ * 2);
 //     mcu.getPin("PB7").connectOutput(radio.SCLK_pin);
        mcu.getPin(3).connectOutput(radio.SCLK_pin); //PB7
        mcu.getPin(1).connectOutput(radio.MOSI_pin); //PB5
        mcu.getPin(2).connectInput(radio.MISO_pin);  //PB6
        mcu.getPin(41).connectOutput(radio.RSTN_pin); //PB1
        mcu.getPin(43).connectOutput(radio.SLPTR_pin);//PB3
        mcu.getPin(44).connectOutput(radio.CS_pin);   //PB4
 
        SPI spi = (SPI)amcu.getDevice("spi");
        spi.connect(radio.spiInterface);
        addDevice("radio", radio);
        radio.RF231_interrupt = mcu.getProperties().getInterrupt("TIMER1 CAPT");
    }
 }

Add sky, micaz, and rfa1 clients and they should all get responses from the server.

Build RPL and radio cycling firmware for even more fun. The RFA1 emulates the hardware csma and random backoff; as yet the Ravens do not so there will be a lot of collisions in contikimac.

Debugging

The AVR Debugger visualizer has a "Source" button that will spawn an avr-objdump -S on the firmware file and read the stdout into assembly and c source panels. If avr-objdump can't find the original c source files the c panel will be empty; similarly avr-objdump won't know if the source files have been changed. Use a rebuilt .elf as necessary, i.e. in cooja select udp-client.c and compile rather than a direct selection of the udp-client.avr-raven file.

Step over, step into, and breakpoints are implemented from either c or assembly source. Registers contents are shown when stepping through assembly. Currently RAM variables can only be examined using the separate Mote Plugin -> Variable Watch panel. Enabling the live update gives a good feel for the contiki program flow.

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