The ELM304 is a low-cost NTSC video signal generator in an 8 pin package. Requiring only an external crystal and a few passive components, this circuit produces a stable raster that is suitable for a variety of video applications. The ELM304 can be `programmed' to generate either a solid white raster or a four-level gray scale pattern simply by changing the logic level at the mode input pin. A supplied internal pullup resistor further simplifies the circuitry when interfacing to mechanical switches.