The HD66520 is a column driver for liquid crystal dot-matrix graphic display systems. This LSI incorporates 160 liquid crystal drive circuits and a 160 x 240 x 2-bit bit-map RAM, which is suitable for LCDs in portable information devices. It also includes a general-purpose SRAM interface so that draw access can be easily implemented from a general-purpose CPU. The HD66520 also has a new arbitration method which prevents flicker when the CPU performs draw access asynchronously. The on-chip display RAM greatly decreases power consumption compared to previous liquid crystal display systems because there is no need for high-speed data transfer. The chip also incorporates a four-level grayscale controller for enhanced graphics capabilities, such as icons on a screen.