A GLCD connected to an AVR microcontroller
The PVG120602EGE is a 128×64 pixel graphic (grey) LCD with lightblue EL backlight and two KS0108 controller chips and one KS0107 line (colums) driver (64 display lines COM1 – COM64) The first KS0108 drives segments 1 to 64 (Y1 – Y64), the second drives segments 65 to 128 (Y65 – Y128). The number of pixels is 128*64 = 8192. The display has an 8-bit databus. When page 0 is active, you can transmit one byte to following Y1, Y2, Y3 until Y64 reached, then switch to the second half (H1)(or use each half sperately) of the display, this is how the picture builds in the RAM memory per line of the display.
The page addressing is from 0 to 7, the LCD has eight pages. Start from page 0 (and X = 0), and transmit one databyte, do this 64 times, then switch to the second half, and repeat until 128th X position reached, this plots the first 8 display lines. The total amount of bytes needed for one frame (one image) is: 2 * 64 pixels * 8 bits = 1024 bytes = 1kbyte (or 8192 pixels / 8 bits = 1024 bytes).
For more detail: A GLCD connected to an AVR microcontroller using ATmega8 microcontroller