MacSamba (Copyright © 2006 - 2009 Nick Howes) is a command line utility program for downloading code into an Atmel ARM CPU via Atmel's SAM-BA and a USB port under Mac OS X. It is released under the GPL. You may use it for free (but donations are gratefully accepted - click on the button below).
I've tested with an Atmel AT91SAM7XC256-EK, and several custom boards using AT91SAM7XC256 and AT91SAM7XC512. It should work with other devices with a few tweaks. MacSamba is slow compared with Atmel SAM-BA (I think because it writes one word at a time). Note that the binary is built for Mac OS X 10.6 Snow Leopard - for use on older versions, you will need to rebuild it.
There may be bugs in the code that cause malfunctions.
Mac OS X
Download the executable, source code and documentation: MacSamba.zip.
Known bugs and issues
Doesn't always recover properly from errors - it you get timeouts or it hangs, reset the target.
You will need to unload the AppleUSBCDC.kext before using MacSamba (which will disable other serial ports):
Send comments, questions, suggestions, bug reports to email@example.com