IIC graphic display

Design Concepts
1

Hi all,

after having serious trouble with a number of different graphic LCDs (see my other thread in Troubleshooting) I am thinking of dropping the “normal” 8bit way altogether and go for a display that is connected to the core via IIC. The benefits in my opinion would be:

  • less error prone regarding the wiring
  • no trouble with negative voltage, as these are usually generated onboard modern displays
  • fully documented modules available at relatively moderate cost

The last bullet is only partly true, I know, but I just looked at the Reichelt catalogue and they offer a 240x128 module for 136 Euro complete with LED backlight and touchscreen  :o.

I have no knowledge of IIC bussing at all, so I wonder how difficult it would be to make the PIC talk to the display using the new IIC C routines Torsten has introduced in MIOS v1.9?

The background of my thoughts is that I need the possibility to display lots of characters in order to label my encoders - there should be about 16 of them grouped around the display, so every pixel is welcome.

Best regards, ilmenator

2

Hi Ilmenator,

in general you can use the IIC functions in order to access the display, it’s very simple - but - I just read in the spec of the LCD you mentioned, that the interface should either be accessed with 100 kHz (MIOS uses 400 kHz), or with 400 kHz and 100 uS delay between the commands — this is extremely slow for a graphical display - I wouldn’t buy it, and would try hard to get the other display running instead (I will give you an answer to the other posting afterwards).

Best Regards, Thorsten.