MAXIM MAX7221 LED Display Driver
The MAX7221 is a compact, serial input/output common-cathode display driver that interfaces microprocessors (µPs) to 7-segment numeric LED displays of up to 8 digits, bar-graph displays, or 64 individual LEDs. Included on-chip are a BCD code-B decoder, mu...
The MAX7221 is a compact, serial input/output common-cathode display driver that interfaces microprocessors (µPs) to 7-segment 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 segment current for all LEDs. The MAX7221 is compatible with SPI™, QSPI™, and MICROWIRE™, and has slewrate-limited segment drivers to reduce EMI.
A convenient 4-wire serial interface connects to all common µPs. Individual digits may be addressed and updated without rewriting the entire display. The MAX7221 also allows the user to select codeB decoding or no-decode for each digit.
The device includes a 150µA 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.
If you intend to use this IC with an Arduino don't forget to check out our HC7219 library, which will allow you to effortlessly drive seven segment and 8x8 matrix LED's including the ability to daisy-chain IC's and create scrolling message displays.
The library can be found in the software section of our support forum here: viewtopic.php?f=58&t=1794
10MHz Serial Interface
Individual LED Segment Control
Decode/No-Decode Digit Selection
150µA Low-Power Shutdown (Data Retained)
Digital and Analog Brightness Control
Display Blanked on Power-Up
Drive Common-Cathode LED Display
Slew-Rate Limited Segment Drivers for Lower EMI (MAX7221)
SPI, QSPI, MICROWIRE Serial Interface (MAX7221)