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At the moment I am building a small demo based on the AVR Raven and Contiki. I was running into some trouble with building the Firmwares on my Mac – this is the documentation of the workarounds.

The Contiki build system depends on some GNU utilities that are not installed. Using the following steps I was able to compile for the “native” (i.a. Mac OS) target:

1. Install GNU binutils using MacPorts.
2. Edit “cpu/native/Makefile.native” and adjust the “Compiler Definitions” section like this:
   
### Compiler definitions
CC = gcc
LD = gcc
AS = as
NM = nm
# Use GNU ar instead of /usr/bin/ar
AR = gar
OBJCOPY = objcopy
STRIP = strip
ifdef WERROR
CFLAGSWERROR=-Werror -pedantic -std=c99 -Werror
endif
CFLAGSNO = -Wall -g -I/usr/local/include $(CFLAGSWERROR)
CFLAGS += $(CFLAGSNO) -D_XOPEN_SOURCE=500 -O
# Simplify ld arguments
#LDFLAGS = -Wl,-Map=contiki-$(TARGET).map,-export-dynamic
LDFLAGS = -Wl


Another issue is the ELF binaries for the AVR Raven boards. These files contain all components of the programs: flash and eeprom
images as well as fuse settings. Unfortunately, avrdude cannot read the ELF format. So you have to extract the flash manually:


$ avr-objcopy -R .eeprom -R .fuse -R .signature -O ihex $NAME.elf $NAME.hex


It works similar for the EEPROM section (where the IP data is stored):

$ avr-objcopy -j .eeprom --set-section-flags=.eeprom="alloc,load" --change-section-lma .eeprom=0 -O ihex webserver6.elf webserver6.eep


You can also check which fuse settings are used:

$ avr-objdump -d -S -j .fuse webserver6.elf
webserver6.elf: file format elf32-avr
Disassembly of section .fuse:
00820000 <__fuse>:
820000: e2 99 ff


The directory structure of Contiki is somewhat overwhelming. I am currently working in these directories:

1. contiki-2.4/platform/avr-ravenlcd: This is where the code for the ATMega3290p lives. Run make here and upload.
2. contiki-2.4/platform/avr-raven: The ATMega1284p code lives here, this is where most patches are. Don’t run make here!
3. contiki-2.4/examples/webserver-ipv6-raven: Run make here for the ATMega1284p code. This builds the webserver code and includes the platform/avr-raven dir.

In addition, I have a serial terminal for debugging output:
screen -U /dev/cu.SLAB_USBtoUART 57600

I have been presenting the mySmartGrid project at C-RaDar, the monthly chaos show in Darmstadt. Someone recorded the show (don’t know who, but thank you!). You can download the MP3 here (german language):

C-RaDar March 2010: mySmartGrid and other stuff

This was a fun experience, kudos go to the C-RaDar people! The picture above: CC-BY-SA-NC by georgia.g, thanks!

All the electric power generated from renewable energy is good – no additional CO2 is produced. Saving energy in general is also a good idea – what you don’t consume, you don’t need to produce. But energy savings require you to understand your own energy consumption – you can’t improve what you can’t measure. A simple energy cost monitor is available for 10 Euro, but it requires you to plug it into different appliances in order to figure out what a specific device consumes. And only the more expensive ones log the power consumption over time, which is pretty interesting.

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