The 7221 is a compact serial input/output common cathode display driver that connects a microprocessor (uPs) to a 7-segment digital LED display with up to 8 bits, a bar chart display, or 64 individual LED displays. The chip includes a BCD code-B decoder, multiscan circuits, segments, and digital drivers, as well as an 8x8 static RAM that stores each digit. Only one external resistor is required to set the segment current of all leds. The 7221 is compatible with SPI ™, OSPI ™, and Microfilament ™ and has a limited conversion rate segment driver to reduce electromagnetic interference. 7221 also allows the user to choose the encoding for each digit -B decoded or not decoded".