SAMA5D3 Xplained .Net Micro Framework Port

I have been working on a port of the .net micro framework for the SAMA5D3 Xplained board for the last few months on and off as I have had the time. The port is based on the 4.4 code of the recent .Net Micro Framework release.

I have now reached the first milestone I have a partially functioning PortBooter. It initialises the hardware and loads the PortBooterDecompressor into SRAM. The PortBooterDecompressor then proceeds to load the PortBooter application into DRAM and jumps to the BootEntry entry point.

The next pieces of work required are to implement the flash and storage drivers. Build the PortBooterClient and test its interaction with the PortBooter.

Later I will develop the additional drivers for the other hardware devices such as USB, I2C, SPI etc. There is still some way to go but I think I have gotten over the first hurdle.

At some point in the future I may simplify the boot process as the decompressed boot loader is not necessary as the PortBooter should fit in the SRAM section of the SAMA5D3 device.

Who is ELMO GMAS

I recently purchased an ATMEL SAMA5D3 Xplained board play around with developing some bare metal ARM code and possibly at some point in the future when I learn a bit more port the .net micro framework to this board. Also this board can run a few different flavours of embedded Linux and is supported by the GCC compiler.

One of the first issues that I came across is when I connected this board was that it is detected as an ELMO GMAS device.

From a quick search I found very little info on why the board was detected as an ELMO GMAS device. Being unsure if this incorrect detection would cause problems with some of the flash tools I set about fixing the problem.

First step is to install the latest SAM-BA tool from ATMEL. This contains the correct driver definition for the board.

• Right click on the ELMO GMAS device and click update driver
• Select Browse my computer for driver software

• Select Let me pick from a list of device drivers on my computer

• Click have disk

• Browse to the driver folder of SAM-BA

• Click ok then click next

• A warning will be displayed, click ok as we are sure that this is the correct driver

• The driver will be installed and the device will show up as an AT91 USB to Serial converter

When the board is booted up in BootROM mode i.e. the JP5 jumper is removed you may have to install a driver for the device. The same AT91 driver can be used

A small ARM race

I have been on a quest lately to find a computer that meets the following criteria:

• Cheap enough to let the kids have it
• I don't really care if the kids break it
• I would like them to maybe learn something about computers, Don’t want app junkies
• I’m old school and want the kids to learn to use a keyboard and a mouse, not mash their paws on a screen
• I can reuse some old hardware, keyboard + mouse + monitor
• Low power consumption

The initial logical answer is the Raspberry PI, yes its cheap but, I’m of the opinion based on discussion on the web that it is a bit under powered as a computer and is more suited to embedded control projects then as a low cost PC like device.

Next up on the list is the Beagleboard-xm it has a bit “power” than the Raspberry PI but it is still considered an embedded board. Having the opportunity to play around with a Beagleboard-xm I was impressed buy its low power consumption, about 750mA @ 5 volts which works out at about 3.75 watts, that was running Ångström while playing 720p video. Unfortunately that is all this board is capable of due to the video processor. But the gnome UI was smooth and use able.

I the installed Ubuntu 12.10 on the micro SD card, which is what most of these small arm board boot from, the result was less that impressive. The response from the UI was pretty slow.

Next on the list is the Pandaboard ES which is a step above the Beagleboard-xm, it has 1GB of ram and a 1.2 Ghz processor and is capable of 1080p. This looks like a pretty capable board but it is more expensive than the Beagleboard-xm. Unfortunately I’ve not had the chance to play with one yet but its on the list of contenders.

I recently found a new entry into the small low powered ARMBrix Zero from a Korean company.

Unfortunately the first batch has sold out. Hopefully there will be more. This is a pretty powerful board it has a Samsung Exynos 5250 dual core ARM Cortex-A15 which is a pretty powerful processor on a board that has 2GB of ram, HDMI, USB 3.0 and a SATA port, 1080p video decoding all for $145 + shipping.

The catch is that there was only one pre order batch available to order which was for an engineering evaluation run. The people behind the board are in the process of testing the design. I for one am eagerly awaiting the next run.

Only problem is I might not let the kids have it :>