Normally I would suggest using the corresponding eval board as a reference, but there appears to be no support for SAM4E-EK in the ASF yet
QuoteWhy SAM4E?A number of reasons;- integral FPU- largest SRAM & flash of all the ARM MCUs- highest number of timers
I've just taken a look in the ASF documentation - whilst the SAM4E-EK board is not supported, the SAM4E devices themselves are, and the typical features present on the eval boards such as LCD displays, QTouch etc are not features i'm remotely interested in using. The target application for my personal dev board is automated control applications, without the need for screens etc.http://asf.atmel.com/docs/latest/
Perhaps as you mention - working with the SAM3X in my own board first would be a better option, as a revision down the road to switch to the SAM4E would be less of a jump, but then again - my board design currently uses a AVR 2560, so that board revision from AVR to SAM3X would be enormous as is, so it seems to make logical sense to jump straight to the intended device.
This switch isn't planned for probably 9 months, I'm just looking to get thoughts into it - but ultimately how to upload to the SAM devices from Atmel Studio, like I say - I've only ever worked 8-bit with the AVR ISP MkII programmer. (or of course the Arduino IDE)
Maybe what I said sounded a little too negative
I wouldn't necessarily recommend SAM3X as first option, I was thinking more of something like SAM3S. I am a believer in incremental change, or at least starting with something that is known to work. I would generally start with an off the shelf eval board, and find an IDE with a project ready for the board (setting up all the project options is tricky enough). Then I go to my own hardware, a different toolchain, and create projects from scratch.
Atmel Studio + Segger Jlink EDU version is a great combo for bare metal programming. The ASF provides a pretty useful peripheral library, but not as easy to use as Arduino libraries.
So go for it, just beware there may be a fairly steep learning curve. Some people enjoy the challenge, and if motivated it's not a problem.
The Cortex M4 parts are pretty beefy, and price not much greater than Cortex M3, so I see the attraction.
This response, and really the question that prompted it is where I'm lacking on the knowledge front mostly. Just taken a look at the Jlink unit (http://www.segger.com/j-link-edu.html), so - are devices like that programmers, or just debuggers for the JTAG interface? (JTAG is something I've never worked with before either)If yes, do they program over an SPI interface the same as the AVR ISP does with the 8bit AVRs?
Saying that, I can't seem to find the 4E chips for sale by any of the big vendors in the UK. Or anywhere outside of the UK for that matter...
Seems like the Atmel Cortex M4 parts are still fairly new.