11th November 2007

LCD screen for LA Fonera

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posted in Hacks |

La Fonera is a really nice toy. I have already deacivated serial console because of playing with IR receiver. So why not playing with serial 128*128 LCD ?

The LCD 128*128 screen module come from 4D Systems and sell by Dontronics. My LCD module is not in product any more. The new OLED model is more rich and include à micro SD reader for storing images and animations. The uLCD model can only display simple stuff (line, cercle, text) and pixel after pixel images.

That's not really important. What we can do with old uLCD can be done with OLED model. Connecting uLCD is quite simple. The LCD module is powered by +5Volts get from La Fonera, serial interfacing is +3.3/0V (like the serial port of the router).

Ok ! Nice ! All i have to do is to connect uLCD with router. Right ? NO !

The first thing we need to do before driving uLCD is to ask the the module to autodetect serial speed. This is done by sending "U" to the module before anything else. But RedBoot talk a lot at boot time and send characters to uLCD module. We can change RedBoot but it's not so easy. And we need to have control over the router if something goes wrong. Don't touch at RedBoot.

The right way is to power up the uLCD module avec complete boot process. All GPIO lines at the back of the router are in use for my i2c bus but i have the Wan Led. We need to remove led and transistor and use this GPIO line (2) with BC547 transistor :

uLCD module can by driven with a simple C program. It's a very basic code that can control uLCD module and send image to the display (slowly).

Here is the stuff :

I'm not sure you can compile from source with your OpenWrt BuildRoot. Build/InstallDev rules from libGD Makefile are... strange.

Maowwwwwwww !

You also need the proc_gpio kernel module from : http://daubau.net/proc_gpio/

So you can power up the module like this :

insmod  proc_gpio
echo 1 > /proc/gpio/2_dir
echo 1 > /proc/gpio/2_out
This entry was posted on Sunday, November 11th, 2007 at 1:57 pm and is filed under Hacks. You can follow any responses to this entry through the RSS 2.0 feed. Both comments and pings are currently closed.

There are currently 2 responses to “LCD screen for LA Fonera”

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  1. 1 On January 10th, 2008, Giuseppe said:

    Hi! I think this is really the best fonera’s hack I’ve ever seen!

  2. 2 On March 9th, 2008, Toxxic said:

    Good Work!
    Maybe you could help me on another Fonera Project:
    I am trying to get JTAG working on La Fonera.
    I am using URJtag http://urjtag.org/
    But it seems that i need some Peeks and Poke (like on old 8bit Machines) to get the Software working with the Flash of the la Fonera. Is anyone interested to help me? I have build a german Wiki Page with some Details.
    http://wiki.freifunk-hannover.de/DebrickLaFonera
    If you need translation on that please write me a PM.
    Maybe it is also possible to Flash LaFonera with a SPI Interface which are used with Microcontrollers.

    TIA and Best Regards
    t0xxiC