Hardware selection UI ===================== For flashing the devices it is very nice if you can have some form of UI and there are many ways of getting there. Output: - Attach the device to a HDMI screen - Attach LEDs to the board - Attach an LCD screen or 7-segment display - Run a web server and access the UI on a phone or similar - Use sound as output - Use the usb gadget framework(e.g. allow to attach to the board with a phone and interact with the device) Input: - No input, just flash what is on the system - Use different USB keys or MMC cards to flash different software - Add buttons to the design - Allow the device to connect to a server and configure the device online - Run a web server Requirements: I looked at the different options and sometimes came up with more options but in the end I wanted something that can work standalone. The idea to have a standalone device that can be taken to evens really sounted very nice. Here are other options I was thinking about and some reasons I did not follow up on them: Runing a webserver was not feasible because one also then needs do networking/discovery and I did not want to dig into that. I might have to combine this with a small display on the device as to publish the IP address of the device. I also looked at using the HDMI port and hooking a keyboard to the device but that really started to become a cumbersome project(We might as well provide documentation on flashing devices from a standard PC). I therefore settled for adding a screen and a few buttons to the flashing device .. image:: images/ui_think.jpg Choice of LCD displays ---------------------- I looked a different displays that where present and available for the Olimex board. This is where a RyPi might have been a no brainer because there are probably many (but still quite expensive) display and solution present. Looking the available options and seeing that in many cases I would have to spend and additional 40 Euro would bring the cost of this "little" hardware project to something I did not feel confortable with specially knowing that one can buy cheap Android phones or tablets bellow that price range. ====================== =========== ============== =========== Device type price connectivity Size ====================== =========== ============== =========== LCD screen +- 40 euro cape quite big LCD screen + touch pad +- 40 euro cape quite big 7Segment display few euro lots of wires quite high 16x2 char display 10 Euro i2c nice fit Nokia 3310 display few euro spi slim fit ====================== =========== ============== =========== Knowing that the Lime also has an expansion board and an UEXT connector it was nice to see that there was an `LCD3310 module`_ and I (wrongly) assumed that the board would be plug an play We later also found that olimex is selling the `display and corresponding connector`_ on their website .. _display and corresponding connector: https://www.olimex.com/Products/Components/LCD/LCD%20DISPLAY%20NOKIA3310/ .. _LCD3310 module: https://www.olimex.com/Products/Modules/LCD/MOD-LCD3310/open-source-hardware .. image:: images/MOD-LCD3310-1.jpg .. toctree::