MAX7219 / MAX7221 are compact, serial input/output common cathode display drivers that connect microprocessors (µP) up to 8 digits to 7-segment digital LED displays, bar graph displays, or 64 individual LEDs. It features an on-chip BCD code-B decoder, multi-scan circuitry, segment and digit drivers, and 8x8 static RAM that stores each digit. Only one external resistor is required to set the segment current for all LEDs.
The convenient 4-wire serial interface connects to all common µPs. Individual digits can be addressed and updated without rewriting the entire screen. MAX7219/MAX7221 also allows the user to select code-B decoding or decoding for each digit.
The devices include a 150µA low power shutdown mode, analog and digital brightness control, a scan limit register that allows the user to display 1 to 8 digits, and a test mode that challenges all LEDs.
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