====== Contiki OS and Sparrow ====== [[http://www.contiki-os.org/|Contiki]] considers itself the "The Operating System for Connecting the Next Billion Devices - the Internet of Things." It's an Internet-connected multi-tasking OS for low-end platforms, like Microcontrollers. Contiki is great for the amazing level of connected functionality it will squeeze out of a five dollar chip. It runs on a vast array of platforms and CPU's. ===== Installing Contiki ===== ==== Toolchain ==== There are two approaches to the toolchain. One is to install all the necessary tools natively on your machine. The other is to get instant-contiki, which is a VM image that works on Windows, Mac or Linux. ==== Download Contiki ==== You need to download a special fork of Contiki to try these changes out. Open a Terminal, and then: $ cd ~ $ git clone https://github.com/narcisaam/contiki-sparrow.git -b sparrow $ cd contiki-sparrow/platform/sparrow If Contiki has a problem with the AVR tools, you will need to follow these steps. It ships with an old version of the tools which does not support the Atmega128rfa1 found on the Sparrow, and then sets those as the default AVR tools even though the tools that ship with this version of Ubuntu are newer. Open a Terminal, and type these: $ sed -i '/avr/d' /home/user/.profile $ sudo aptitude update $ sudo apt-get install avr-libc gcc-avr binutils-avr avrdude git libc6-i386 Then log out of the machine and back in again (or restart it). ===== Setting Up ===== ==== Default avrdude port ==== Connect the Sparrow board to your computer through USB. Once this is done, you'll likely see a new //ttyUSB// port appear in ///dev//. In the folder ///contiki-sparrow/platform/sparrow// edit Makefile.sparrow, and change the default avrdude port to match your local settings. This only needs to be done once ever. From now on in this tutorial we'll assume the board is connected to //ttyUSB0//, but you can modify according to your local settings. AVRDUDE_PORT ?= /dev/ttyUSB0 ==== MAC Address / Node Number ==== Each node needs a unique MAC address. The sparrow platform expects to find the MAC address as the first 8 bytes in EEPROM. There is a special program just to program the MAC address. In the ///contiki-sparrow/platform/sparrow// folder, check up //tools/set-eeprom/set-eeprom.c// - it should look like this: typedef unsigned int uint8_t __attribute__((__mode__(__QI__))); uint8_t rf_channel[2] __attribute__((section(".eeprom"))) = {26, ~26}; uint8_t mac_address[8] __attribute__((section(".eeprom"))) = {0x02, 0x11, 0x22, 0xff, 0xfe, 0x33, 0x44, NODE}; It uses the same first 7 bytes, and lets you choose a different number for the last. From this point forward, we will refer to that last digit of the MAC address as the "Node number". To assign a node number to your node: $ cd tools/set-eeprom $ make NODE=3 AVRDUDE_PORT=/dev/ttyUSB0 ===== Hello World ===== Go back in your terminal to ///contiki-sparrow/platform/sparrow// and type... $cd tests/hello-world $make upload $make login Working correctly, you should see this: *******Booting Contiki 2.5******* MAC address 2:11:22:ff:fe:33:44:3 nullmac sicslowmac, channel 26, check rate 65535 Hz Routing Enabled Autostart other processes IP addresses [4 max] fdfd::3 fe80::11:22ff:fe33:4403 Hello, world ==== Ping ==== Now that we know the node itself is working and printing OK, we want to make sure two nodes can talk. The best way to do this is with a ping. This requires two nodes. If you already have hello-world on one node, the easiest thing to do is to put //ping-ipv6// on a second node, and ping the other. So for this example, say we already have //hello-world// working on node 3 on ///dev/ttyUSB0//. We'll connect a second node to the computer, and presume it's connected to ///dev/ttyUSB1// and it's already been configured with node address 1. For this node, we'll need to compile and upload the //ping-ipv6// app and specify the node we'll want to ping. $ cd tests/ping-ipv6 $ make upload AVRDUDE_PORT=/dev/ttyUSB1 NODE=3 $ make login AVRDUDE_PORT=/dev/ttyUSB1 Note that you have to pass the node number of the node you want to ping (NODE=3 in this example). Working correctly, you will see this: connecting to /dev/ttyUSB1 (57600) [OK] Power-on reset. External reset! *******Booting Contiki 2.5******* MAC address 2:11:22:ff:fe:33:44:1 nullmac sicslowmac, channel 26 In Process PING6 Wait for DAD IP addresses [4] fdfd::1 fe80::11:22ff:fe33:4401 Sending Echo Request to fdfd:0000:0000:0000:0000:0000:0000:0003 from fdfd:0000:0000:0000:0000:0000:0000:0001 Echo reply received. Sending Echo Request to fdfd:0000:0000:0000:0000:0000:0000:0003 from fdfd:0000:0000:0000:0000:0000:0000:0001 Echo reply received. Sending Echo Request to fdfd:0000:0000:0000:0000:0000:0000:0003 from fdfd:0000:0000:0000:0000:0000:0000:0001 Echo reply received. Sending Echo Request to fdfd:0000:0000:0000:0000:0000:0000:0003 from fdfd:0000:0000:0000:0000:0000:0000:0001 Echo reply received. Sending Echo Request to fdfd:0000:0000:0000:0000:0000:0000:0003 from fdfd:0000:0000:0000:0000:0000:0000:0001 Echo reply received. END PING6 ==== UDP ==== Finally, we will want to be sure that two nodes can exchange real application data between them. We can do so with the UDP client/server test. Again, this requires two nodes. One node contains the server program, the other contains the client. When making the client, we need to tell it where to find the server by specifying NODE= the Node# of the server. $ cd tests/udp-ipv6 $ make NODE=3 -j10 $ make udp-client.sparrow.u AVRDUDE_PORT=/dev/ttyUSB1 NODE=3 $ make udp-server.sparrow.u login AVRDUDE_PORT=/dev/ttyUSB0 Working correctly, you'll see something like the following. The exact numbers will depend on the timing of when you do the 'make login'. connecting to /dev/ttyUSB0 (57600) [OK] Power-on reset. External reset! *******Booting Contiki 2.5******* MAC address 2:11:22:ff:fe:33:44:3 nullmac sicslowmac, channel 26 IP addresses [4] fdfd::3 fe80::11:22ff:fe33:4403 UDP server started Server IPv6 addresses: fdfd::3 fe80::11:22ff:fe33:4403 +READY Server received: 'Hello 2 from the client' from fdfd::1 Responding with message: Hello from the server! (1) Server received: 'Hello 3 from the client' from fdfd::1 Responding with message: Hello from the server! (2) Server received: 'Hello 4 from the client' from fdfd::1 Responding with message: Hello from the server! (3) Server received: 'Hello 5 from the client' from fdfd::1 Responding with message: Hello from the server! (4) Server received: 'Hello 6 from the client' from fdfd::1 Responding with message: Hello from the server! (5) Server received: 'Hello 7 from the client' from fdfd::1 +OK PASS ====== Timers & Events in Contiki ====== This tutorial will show how to make use of timers in Contiki. It will also give a basic into to events. ===== Processes ===== All Contiki programs are processes. A process is a piece of code that is executed regularly by the Contiki system. Processes in Contiki are typically started when the system boots, or when a module that contains a process is loaded into the system. Processes run when something happens, such as a timer firing or an external event occurring. Code in Contiki can run in one of two execution contexts: cooperative or preemptive. Code running in the cooperative execution context is run sequentially with respect to other code in the cooperative context. Cooperative code must run to completion before other cooperatively scheduled code can run. Preemptive code may stop the cooperative code at any time. When preemptive code stops the cooperative code, the cooperative code will not be resumed until the preemptive code has completed. The concept of Contiki's two scheduling contexts is illustrated above. Processes always run in the cooperative context. The preemptive context is used by interrupt handlers in device drivers and by real-time tasks that have been scheduled for a specific deadline. An example process that receives events and prints out their number: #include "contiki.h" PROCESS(example_process, "Example process"); AUTOSTART_PROCESSES(&example_process); PROCESS_THREAD(example_process, ev, data) { PROCESS_BEGIN(); while(1) { PROCESS_WAIT_EVENT(); printf("Got event number %d\n", ev); } PROCESS_END(); } The complete reference on Contiki processes can be found [[https://github.com/contiki-os/contiki/wiki/Processes|here]]. Contiki provides three kinds of timers: * **Simple timer:** The timer library provides functions for setting, resetting and restarting timers, and for checking if a timer has expired. An application must "manually" check if its timers have expired, meaning that this library does not post an event when the timer expires, so we must implement a routine that checks the timer for expiration. * **Callback timer:** The callback timer library provides the same functions as above, but when the timer expires can callback a C function. * **Event timer:** The same as above, with the difference that instead of calling a function, when the timer expires it post an event signalling the timer expiration. More information on timer can be found on the Contiki's [[https://github.com/contiki-os/contiki/wiki/Timers|wiki page on timers]]. ===== The Event Timer ===== The etimer (Event timer) will post an event when the timer is expiring. Since it posts an event you will need to have a process around it to handle the event. PROCESS_THREAD(etimer_process, ev, data) { static struct etimer et; PROCESS_BEGIN(); /* set timer to expire after 5 seconds */ etimer_set(&et, CLOCK_SECOND * 5); while(1) { PROCESS_WAIT_EVENT(); /* Same thing as PROCESS_YIELD */ if(etimer_expired(&et)) { /* Do the work here and restart timer to get it periodic !!! */ printf("etimer expired.\n"); etimer_restart(&et); } } PROCESS_END(); } In the above code the process is defined by PROCESS_THREAD which takes a name, an event variable and an event data variable as the arguments. When an etimer expires the event variable will be set to PROCESS_EVENT_TIMER and the event data variable will be set to point to the specific timer. Using that information the above example could also look like: PROCESS_WAIT_EVENT_UNTIL(ev == PROCESS_EVENT_TIMER && data == &et); /* Do the work here and restart timer to get it periodic! */ printf("etimer expired.\n"); etimer_restart(&et); But when waiting for this event in this way -- all other events will be ignored so the first approach is more flexible as this will enable handling multiple types of events more easily. ===== The Shell ===== The shell is a very powerful feature of Contiki. Within this OS lies a fully-featured command shell. The shell in the sparrow platform is a subset of the full Contiki shell, including only the shell modules which have been proven to work on this platform. ==== Building ==== $ cd tests/shell $ make upload $ make login ==== Running ==== If successful, you'll see this: connecting to /dev/ttyUSB1 (57600) [OK] Power-on reset. External reset! *******Booting Contiki 2.5******* MAC address 2:11:22:ff:fe:33:44:1 nullmac sicslowmac, channel 26 Contiki command shell Type '?' and return for help 68.1: Contiki> IP addresses [4] fdfd::1 fe80::11:22ff:fe33:4401 === help === Now, try some of the commands, like 'help': Available commands: ?: shows this help binprint: print binary data in decimal format blink [num]: blink LEDs ([num] times) echo : print exit: exit shell hd: print binary data in hexadecimal format help: shows this help kill : stop a specific command killall: stop all running commands netstat: show UDP and TCP connections null: discard input ping : ping an IP host ps: list all running processes quit: exit shell randwait : wait for a random time before running a command repeat === blink & kill === Try "blink 100 &" to start blinking the LED's for 100 times. Notice the '&' at the end of that! You should now see Sparrow's LED flash on and off repeatedly. Then type "kill blink" when you're done admiring your blinking lights. === ping === We can also ping from within the shell! 68.1: Contiki> ping fdfd::3 SEND 13 bytes ping fdfd::3 Sending Echo Request to fdfd:0000:0000:0000:0000:0000:0000:0003 from fdfd:0000:0000:0000:0000:0000:0000:0001 Other ICMP6 message received. Echo reply received. ====== Using SLIP ====== ===== What is SLIP? ===== SLIP is the "mostly obsolete" wikipedia:Serial Line Internet Protocol. "On personal computers, SLIP has been largely replaced by the Point-to-Point Protocol (PPP), which is better engineered, has more features and does not require its IP address configuration to be set before it is established. On microcontrollers, however, SLIP is still the preferred way of encapsulating IP packets due to its very small overhead." Contiki uses SLIP to bridge the wireless IPv6 network onto a PC via a USB connection. So with your Sparrow plugged into your PC, and the right software running on each, traffic from the wireless IP network can reach your site-wide Ethernet network and potentially beyond. On Sparrow, there is only one UART exposed. This means we have to choose between reading debug messages and connecting to our PC via SLIP. This change is exposed by adding "WITH_SLIP=1" to the makefile or command line for any particular project. Projects made "WITH_SLIP" will expect to talk to a slip tunnel on the PC side. Speaking of the PC side... In order for SLIP to work, something on the host PC has to be listening. Using Instant Contiki, the 'tunslip6' will do this. Running it in Linux creates a 'tun0' interface which gives the connected Sparrow an address of aaaa::1 on your local network. ===== Building ===== First, built the tunslip6 tool. This works without modification on Instant Contiki. $ cd tools $ make tunslip6 Now make and upload the border router itself. Be sure to include "WITH_SLIP=1" to turn on slip for this node, and "WITH_WEBSERVER=0" to exclude a web server from this node. $ cd examples/ipv6/rpl-border-router $ make TARGET=sparrow savetarget $ make WITH_SLIP=1 WITH_WEBSERVER=0 -j10 $ make upload AVRDUDE_PORT=/dev/ttyUSB0 ===== Connecting ===== Ok, now it's built. Let's bring up the slip interface on Linux. Note that the baud rate here has to match the baud rate in the uart setup on the board, which is currently 38400. That's a little slow, but I'll work on bringing it up in future revisions. Also note the "v6" switch. That turns on maximum debugging output so we can follow along. $ sudo ../../../tools/tunslip6 aaaa::1/64 -s /dev/ttyUSB0 -B 38400 -v6 ********SLIP started on ``/dev/ttyUSB0 opened tun device ``/dev/tun0 ifconfig tun0 inet `hostname` up ifconfig tun0 add aaaa::1/64 ifconfig tun0 tun0 Link encap:UNSPEC HWaddr 00-00-00-00-00-00-00-00-00-00-00-00-00-00-00-00 inet addr:127.0.1.1 P-t-P:127.0.1.1 Mask:255.255.255.255 inet6 addr: aaaa::1/64 Scope:Global UP POINTOPOINT RUNNING NOARP MULTICAST MTU:1500 Metric:1 RX packets:0 errors:0 dropped:0 overruns:0 frame:0 TX packets:0 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:500 RX bytes:0 (0.0 B) TX bytes:0 (0.0 B) tun0 Link encap:UNSPEC HWaddr 00-00-00-00-00-00-00-00-00-00-00-00-00-00-00-00 inet addr:127.0.0.1 P-t-P:127.0.0.1 Mask:255.255.255.255 inet6 addr: aaaa::1/64 Scope:Global UP POINTOPOINT RUNNING NOARP MULTICAST MTU:1500 Metric:1 RX packets:0 errors:0 dropped:0 overruns:0 frame:0 TX packets:0 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:500 RX bytes:0 (0.0 B) TX bytes:0 (0.0 B) IP addresses [4 max] fdfd::3 fe80::11:22ff:fe33:4403 RPL-Border router started *** Address:aaaa::1 => aaaa:0000:0000:0000 SIN: 10 Got configuration message of type P Setting prefix aaaa:: created a new RPL dag Server IPv6 addresses: aaaa::11:22ff:fe33:4403 fdfd::3 fe80::11:22ff:fe33:4403 It's helpful that tunslip6 is putting through the debug messages from the Sparrow. So we can see the boot-up process complete successfully. ===== Ping ===== We should now be able to ping the border router from the host PC. First, we can ping its auto-configured aaaa::/64 address $ ping6 aaaa::11:22ff:fe33:4403 PING aaaa::11:22ff:fe33:4403(aaaa::11:22ff:fe33:4403) 56 data bytes 64 bytes from aaaa::11:22ff:fe33:4403: icmp_seq=1 ttl=64 time=66.1 ms 64 bytes from aaaa::11:22ff:fe33:4403: icmp_seq=2 ttl=64 time=68.6 ms 64 bytes from aaaa::11:22ff:fe33:4403: icmp_seq=3 ttl=64 time=66.2 ms ===== Nodes Beyond the Border ===== We want to reach more nodes than just the one connected. So let's add a route on the host PC. This "route add" command tells Ubuntu that whenever it wants to reach a node whose IP starts with fdfd::/64, it can send that through the tun0 interface. $ sudo route -A inet6 add fdfd::/64 dev tun0 $ netstat -r6 Kernel IPv6 routing table Destination Next Hop Flag Met Ref Use If aaaa::/64 :: U 256 0 0 tun0 fdfd::/64 :: U 1 0 0 tun0 Now that we have the route set up, we can put another node on the network, and ping that. Put anything that speaks RPL on fdfd::1, for example rpl-collect/sender $ cd examples/ipv6/rpl-collect $ make TARGET=sparrow savetarget $ make udp-sender.sparrow.u AVRDUDE_PORT=/dev/ttyUSB1 -j10 Now see that we can ping it ok: $ ping6 fdfd::1 PING fdfd::1(fdfd::1) 56 data bytes 64 bytes from fdfd::1: icmp_seq=1 ttl=64 time=67.8 ms 64 bytes from fdfd::1: icmp_seq=2 ttl=64 time=66.3 ms ====== Using the Webserver ====== From a PC on our network, we want to view a web page served up by any node on our wireless IP network. This will allow us to look at sensor values or other data stored there. ===== Building ===== We'll put the rpl-border-router (with no webserver) on the node connected to the PC, and talk SLIP over USB between it and the PC. The other node will run webserver-ipv6 with 'webserver-nano'. $ cd examples/ipv6/rpl-border-router $ make TARGET=sparrow savetarget $ make upload WITH_WEBSERVER=0 WITH_SLIP=1 AVRDUDE_PORT=/dev/ttyUSB0 -j10 $ cd examples/webserver-ipv6 $ make TARGET=sparrow savetarget $ make WITH_WEBSERVER=webserver-nano -j10 $ make upload login WITH_WEBSERVER=webserver-nano AVRDUDE_PORT=/dev/ttyUSB1 ===== Running ===== This has to be done in another window, because "make login" above took over that window. Here we will bring up the tunnel, and try everything out, one thing at a time. Ping the router, ping the webserver, do the 'get'. $ sudo ../../../tools/tunslip6 aaaa::1/64 -s /dev/ttyUSB0 -B 38400 -v6 $ sudo route -A inet6 add fdfd::/64 dev tun0 $ ping6 fdfd::3 $ ping6 fdfd::1 $ curl -g "http://[aaaa::11:22ff:fe33:4401]/" Here's what success looks like! $ curl -g "http://[aaaa::11:22ff:fe33:4401]/" Contiki-nano 
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This page has been sent 2 times Plus here's the Wireshark summary of this conversation: No. Time Source Destination Protocol Info 1 0.000000 aaaa::1 aaaa::11:22ff:fe33:4401 TCP 36067 > http [SYN] Seq=0 Win=5760 Len=0 MSS=1440 TSV=87387016 TSER=0 WS=5 2 0.242296 aaaa::11:22ff:fe33:4401 aaaa::1 TCP http > 36067 [SYN, ACK] Seq=0 Ack=1 Win=1220 Len=0 MSS=1220 3 0.242351 aaaa::1 aaaa::11:22ff:fe33:4401 TCP 36067 > http [ACK] Seq=1 Ack=1 Win=5760 Len=0 4 0.242589 aaaa::1 aaaa::11:22ff:fe33:4401 HTTP GET / HTTP/1.1 5 0.630341 aaaa::11:22ff:fe33:4401 aaaa::1 TCP [TCP segment of a reassembled PDU] 6 0.630388 aaaa::1 aaaa::11:22ff:fe33:4401 TCP 36067 > http [ACK] Seq=165 Ack=86 Win=5760 Len=0 7 0.898326 aaaa::11:22ff:fe33:4401 aaaa::1 TCP [TCP segment of a reassembled PDU] 8 0.898360 aaaa::1 aaaa::11:22ff:fe33:4401 TCP 36067 > http [ACK] Seq=165 Ack=113 Win=5760 Len=0 9 1.258323 aaaa::11:22ff:fe33:4401 aaaa::1 TCP [TCP segment of a reassembled PDU] 10 1.258369 aaaa::1 aaaa::11:22ff:fe33:4401 TCP 36067 > http [ACK] Seq=165 Ack=408 Win=6432 Len=0 11 1.550390 aaaa::11:22ff:fe33:4401 aaaa::1 TCP [TCP segment of a reassembled PDU] 12 1.550426 aaaa::1 aaaa::11:22ff:fe33:4401 TCP 36067 > http [ACK] Seq=165 Ack=490 Win=6432 Len=0 13 1.842334 aaaa::11:22ff:fe33:4401 aaaa::1 TCP [TCP segment of a reassembled PDU] 14 1.842364 aaaa::1 aaaa::11:22ff:fe33:4401 TCP 36067 > http [ACK] Seq=165 Ack=567 Win=6432 Len=0 15 2.098333 aaaa::11:22ff:fe33:4401 aaaa::1 TCP http > 36067 [FIN, ACK] Seq=567 Ack=165 Win=1220 Len=0 16 2.098508 aaaa::1 aaaa::11:22ff:fe33:4401 TCP 36067 > http [FIN, ACK] Seq=165 Ack=568 Win=6432 Len=0 17 2.334295 aaaa::11:22ff:fe33:4401 aaaa::1 TCP http > 36067 [ACK] Seq=568 Ack=166 Win=1220 Len=0