I2CWRITE not writing anything on PIC18F45K80

[CuriousOne]

Ok, here are the answers.

ST7920 based display modules have great advantages over any common LCD controllers:

1. They are physically and pin to pin compatible with common 1602 LCD modules, HD44780 based.
2. In most applications they work as a drop in replacement for 1602 display (no need for code change), providing better visual appearance on screen, due to having far higher number of pixels - 144x32 vs 80x16 on common 1602 LCD
3. They have built-in 8192 characters for Chinese language, so whenever you need to use them, you don't need to mess with the graphics statements at all, just send an unicode code of char to display.
4. They have graphical mode, which also has hardware overlay and scroll function - text output (and CGRAM) in standard 1602 mode and graphics data are stored in separate areas of memory, which allows many fancy things to be done, like smooth parallax scrolling at different speeds, without need of software overlay calculation.
5. Due to high pixel density, in size of 1602 LCD, where you have 16 chars @ 2 rows, with 5x7 pixel fonts, here you can have 18 chars @ 4 rows, with 8x8 pixel fonts.

For the timing, datasheet shows nanosecond grade timings for writing the display. However, the above mentioned LCDOUT delays are practical observations - if I reduce them further, display gets garbled. So most likely, PBP is messing something up.

The datasheet mentions following way of graphic data sending, which I'm following in my code:

Graphic display RAM supports 64x256 bits bit-mapped memory space. GDRAM address is set by writing 2
consecutive bytes for vertical address and horizontal address. Two-bytes data write to GDRAM for one address.
Address counter will automatically increase by one for the next two-byte data. (This appears to be not working in the way you think it does) The procedure is as followings.
1. Set vertical address（ Y） for GDRAM
2. Set horizontal address（ X） for GDRAM
3. Write D15〜D8 to GDRAM 中(first byte)
4. Write D7〜D0 to GDRAM 中(second byte)


Yes I know there are other graphical displays there, including OLED and color TFTs, but no matter how hard I tried, I was never able to use any code provided here - 99% not compiling, giving some errors, and ones that compile, will never work. So I have to "develop" my own code for Graphic displays. So far these are for ST7920 and WS0010.