The STV9420/21 is an ON SCREEN DISPLAY for monitor. It is built as a slave peripheral connected to a host MCU via a serial I2C bus. It includes a display memory, controls all the display attributes and generates pixels from the data read in its on chip memory. The line PLL and a special slice interpolator allow to have a display aspect which does not depend on the line and frame frequencies. I2C interface allows MCU to make transparent internal access to prepare the next pages during the display of the current page. Toggle from one page to another by programming only one register. 4 x 8 bits PWM DAC are available (STV9421) to provide DC voltage control to other peripherals. The STV9420/21 provides the user an easy to use and cost effective solution to display alphanumeric or graphic information on monitor screen. October 1995