MAX7221

The MAX7219/MAX7221 are compact, serial input/output common-cathode display drivers that interface microprocessors (Ps) to 7-egment numeric LED displays of up to 8 digits, bar-graph displays, or 64 individual LEDs. Included on-chip are a BCD code-B decoder, multiplex scan circuitry, segment and digit drivers, and an 8x8 static RAM that stores each digit. Only one external resistor is required to set the segmentcurrent for all LEDs. The MAX7221 is compatible with SPI™, QSPI™, and Microwire™, and has slew-ratelimited segment drivers to reduce EMI.

A convenient 3-wire serial interface connects to all common Ps. Individual digits may be addressed and updated without rewriting the entire display. The MAX7219/MAX7221 also allow the user to select code-B decoding or no-decode for each digit.

The devices include a 150A low-power shutdown mode, analog and digital brightness control, a scanlimit register that allows the user to display from 1 to 8 digits, and a test mode that forces all LEDs on.