Description The HD66421 drives and controls a dot matrix graphic LCD(Liquid Crystal Display) using a bit-mapped method. It provides a highly flexible display through its on-chip display RAM, in which each two bits of data can be used to turn on or off one dot on LCD panel with four-level grey scale. A single HD66421 can display a maximum of 160x100 dots using its powerful display control functions. It can display only eight lines out of one hundred lines.