WT3020 is a really tiny, cheap and yet powerful device and I have this idea that it would be very cool to embed a small LCD display in it. I think this could be used for different kinds of projects.
On the wiki it is stated that the device has 4 unused GPIOs.
On ebay there are cheap tiny 128X64 OLED displays with SSD1306 controller. here is an example
So my thinking is would it be possible to communicate with such display through the GPIOS?
These displays support either SPI or I2C. I think it would be best to use the I2C bus because then you have 2 GPIOs left for other things like buttons, switches, leds...
My question is what would be the steps involved to get this I2C display working on WT3020 running Openwrt?
I have found the ssd1306 I2C linux driver http://lxr.free-electrons.com/source/dr … sd1307fb.c
So the steps to achieve my goal would be:
1. Need to modify pull-down GPIOs to pull-up.
2. Need to establish I2C bus over gpio http://wiki.openwrt.org/doc/hardware/port.i2c
3. Need to make ssd1306 driver use I2C bus
4. Need an example on how to display something on the connected display.
Is my reasoning correct?
I do not know how to do step 3. I asked around and it was mentioned that I might need a custom device tree overlay. But I don't have knowledge on how device tree and overlays work. Can somebody step in with any links or explanations or examples?
I do not know how to do step 4 either but I think I could adapt the Adafruit example programs for ssd1306 on raspberry pi?
I think it would be really great to get this working so I will really appreciate any input from you all!
Thank you in advance 
(Last edited by pingo on 15 May 2015, 12:41)