Hi Batu C.,

What exactly do you need:
1. Want to know how to monitor current, voltage, etc....
2. Want to know how to write to GLCD and show something on the LCD screen. What information is to be displayed, is another matter, and it is covered in Question 1.

The block diagram was good. But need more specifics. How is CPU connected to LCD? From your drawing, it seems you are using IIC for GLCD. You cannot connect IIC to GLCD(I suppose). What is connected at the other end of IIC? Explain the path between the CPU and the GLCD?

Method of writing commands to GLCD are almost the same as 16x2 LCD, but you have to use 8-bit databus for GLCD. CS1 is ChipSelect for the left half of the LCD, and the CS2 is for the right half of the LCD. Basically it is 2 nos of 64x64 LCDs-in-one.
One more point, there is Vee pin (-5V). Connect a pot between Vee and Vcc, Connect the middle terminal of POT to Vo. I remember, I had wasted a full day trying to figure out what to give on Vo, since the lcd display was showing charachters but were very dim.