View ks2501 datasheet:

MARCH. 1998 DATA SHEET KS2501 OSD PROCESSOR FOR MONITORS KS2501 OSD PROCESSOR The KS2501 is used to display some characters or symbols 24-DIP-300 on a screen of monitor. Basically, the operation is to control the internal memory on chip and generate the R,G,B signals for some characters or symbols. The R,G,B signals are syn- chronized with the horizontal sync. Then the R,G,B signals are mixed with the main video signal in the Video Amp IC. The font data for characters or symbols are stored in the inter- nal ROM. This stored data are accessed and controlled by the control data from a micro controller. The control data are transmitted through the I2C bus. All timing control signals including the system clock are synchronized with the horizon- tal sync. Therefore there is a