Lately I’ve been busy with university stuff. In particular, my final year project, which is investigating Controller Area Networks, in the context of the Atmel AT91SAM7X256 MCU. These microcontrollers are a low-cost system-on-chip based around the ARM7TMDI core. This particular one includes 64KB RAM, 256KB flash, RS-232, device-side USB 2.0, 10/100Mbps ethernet, and of course, a CAN interface.

Kernel

You don’t have to use a kernel of course, you can code bare-iron, but I decided to go with a multitasking kernel to make my life easier — I can code each thread to do something basic, and let the kernel manage the IPC and task switching for me, hooking them together. There are a few options out there, but so far the option I’m liking the most, is the FreeRTOS kernel. This kernel is free software under the GNU GPL, and supports many platforms, including ARM7.

Toolchain

There are a few compiler toolchains you can use for this board. The DVD that comes with the board, includes a version of IAR Embedded Workbench, which isn’t too bad, but unless you pay for a license, your code size is limited to 32KB. The GNU toolchain however, is very mature for the ARM7 platform… and getting a toolchain up and running isn’t too difficult.

FreeRTOS can be built using IAR.

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