ARM microcontrollers are great for running embedded linux. This project got some power as it uses 2MB SRAM, Philips LPC22xx processor that runs at 60MHz, SD/MMC card slot, NIC 10Mbit RTL8019 Ethernet chip.

If you dare to recreate this project - here are Eagle files needed. Also you need to load uClinux in to RAM memory with bootloader and uClinux source code with proper MMC/SD and network card drivers. Once everything is set - you can run various linux based servers like http, smtp etc. and access them via your computer client programs like browsers, pop clients - you name it.

This is great project demonstrating an organic LED display interface. ARM7 (AT91SAM7S64) microcontroller displays and analog clock face on OLED screen which has 18 bit color range and is low power.

Project uses DS3234S RTC IC that is interfaced to ARM7 microcontroller via SPI port. Another interesting feature is that clock uses a light sensor TSL256 which enables to adjust displays brightness according to ambient light level. So in dark environment clock is dimmed while in bright room brightness is high. OLED allows 16 brightness levels. Project description, circuit and assembly source code for gnu compiler can be viewed here.

This GPS based car speed and position logger is based on Olimex LPC2148  project board, which is wired to GPS receiver. GPS receiver is interfaced via serial port - so not much of soldering.

Software is based on FreeRTOS where ChanFS file system is used for storing logged data in SD/MMC FAT16 formatted card. It also has USB serial port emulation which enables to monitor NMEA sequences or simply retrieve logs as from mass storage device without removing CD/MMC card. Project files for WinARM GCC can be downloaded here.

This is small blinking LED demo application for LPC2103 Olimex board. Project compilation was made under Linux by using GCC tools and debugged openOCD debugging software.

Benedikt Sauter describes the process of building project with arm-elf-gcc and debugging with openOCD via JTAG interface. Follow these steps and you will make your first ARM7 project under Linux. Necessary project files can be downloaded here.

ARM microcontrollers are 32 bit systems with high potential. It is enough power to run small operation systems like uClinux. The only limitation is that operations systems require much more program memory than internal chip memory can provide. Ulrich Radig used a NXP LPC2294 ARM7 microcontroller which carries 256K of internal Flash memory which is enough to place a boot-loader which loads uClinux kernel to SRAM.

It interesting how he solved low memory problem. SD card was split in to two partitions where one partition FAT16 was used to store kernel which has to be loaded to memory, second is Linux (ext2) partiion for custom use. To support this he has written a simple driver. When Linux is loaded, it is easy to run various custom programs like web servers, and so on.