Its been a few week so its been enough time to give me a good handle on the kit and give a fair minded review from my own perspective. The first thing I’m going to talk about is rubbish! actually nothing to do with the end product but essential none the less. I’m sure you’ve either heard of, or even experienced the horror stories about inadequate packaging, from LCD screens “protected” by a thin sheet of bubble wrap and an envelope, to equally thin envelopes containing thousands of pieces of fragmented plastic… I was very heartened to see how Olimex sent the package (which arrived promptly unlike the USPO, it seems UPS don’t just leave stuff in a warehouse for over a week at a time…) Inside the thick waterproof UPS plastic bag was a stout quality carton, inside which were a fair number of hard foam blocks containing the above pictured boxes, all with their own bubble wrapped packages – some with more foam inside. Its really nice to see that a company is serious about getting their kit to you in good condition rather than shave a few cents of the price (which is ultimately self defeating…)
Build quality wasn’t restricted to the boxes however, throughout build quality is good and I have to say that the products are basically at least as advertised ! so there’s a turn up for the books!
The (A20) board is quite well thought out and the number of GPIO pins is massively generous, more than I’ve seen in a number of FPGA boards! Given that just about every peripheral connection of the SoC is brought out to a connector this is quite extraordinary, and very nice to see… One thing you’ll want to bring to the party is a serial to USB connector, if like me you have a max232 breakout board and separate serial-usb cable then you’ll need to power the level shifter, usefully the +5 pin of GPIO socket 2 is right next the the 3v3 debug socket…
There are really only two criticisms I can level at the Olimex kit, the hardware and software… don’t worry not all of the hardware and not all of the software!
First of all the hardware issue – alongside the A20 I ordered a touch screen LCD, I can live with the fact that the touch screen is not attached (A little double sided tape soon sorts that) but after carefully aligning the right hand side of the display area, I discovered it was over two millimetres smaller than the actual display area… not ideal… additionally as to be expected from a resistive touch screen, accuracy is somewhat of an issue – no great surprise. If you want a kiosk type screen with large buttons, then its just the ticket, however gtk/system menu selection even with a stylus are going to be problematic especially near the screen edges.
The software issue – is mainly due to the nature of the flexibility of the board, it could easily be put in an industrial setting running headless, but then just as easily it could slot into a hand held games system. Due to this even the “ultimate” SD image, should only really be consider as your starting point, although I’ve not done much with the Android image I get the feeling from the forum that the same is the case there…
Olimex has done a lot of the work for us though, their various blog posts contain many useful nuggets of information that can be used to build your own image. Oddly though debootstrap hasn’t been mentioned, basically given a bootable image and a kernel you can install Debian onto new media very easily.
So what can be done with an A20 system? Well actually quite a lot, aside from an LCD display you can as easily link it to a HDMI or VGA monitor. When doing Kernel hacking the previously mentioned debug serial port is very useful. There is even a SATA interface, however you’ll need a low power device (SSD for example) if you want to do anything on battery power, indeed even with a 6600mAh battery you’re probably pulling more current than you should even with an SSD device. 3D support for the time being is with a binary blob – *sigh* – EGL is a little picky however, for example I couldn’t get GLFW 3.1 to open a window, that said when I changed my framework back to using Xlib everything just worked, but then again my Java wrapper for GLES is working very erratically !
My overall impression of the Olimex components is really very favourable especially their LCD modules which are very sensibly priced. Once you get time to dig into the internals of the A20 it’s really a very nice piece of kit, if you’d set out to build a board without comprise I really don’t think you’d be upset if you came up with this product, it genuinely does get the most out of the A20 SoC.
Given that I want to use a SATA device I’m going to have to look at the battery side of things again and I do fancy stripping that zippy keyboard from its case… I’m going to have to have a think about what kind of enclosure I’m going to put all this kit into (sensible enclosure suggestions most welcome!) … oh and there’s a honeymoon coming up, so it could be a while before my device is fully built…