The MAX7219 is a compact, serial input/output common-cathode display driver that interfaces microprocessors (μPs) to 7-segment numeric LED displays (up to 8 digits), bar graph displays, or 64 individual LEDs. It includes a built-in 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 MAX7219 is compatible with SPI, QSPI, and Microwire, and features slew-rate limited segment drivers to reduce EMI. It also has a convenient 3-wire serial interface that connects to all common μPs. Individual digits can be addressed and updated without rewriting the entire display. The MAX7219 also allows the user to select code-B decoding or no-decode for each digit. The device includes a low-power shutdown mode of 150μA, analog and digital brightness control, a scan-limit register that allows users to display from 1 to 8 digits, and a test mode that forces all LEDs on.

• A single module can drive an 8x8 common-cathode dot matrix display.
• Module operating voltage: 5V.
• Module size: 12.8 cm X 1.3 cm.
• Module with input and output interfaces, support for daisychaining multiple modules.

The wiring is as follows:

• VCC → 5V
• GND → GND
• DIN → P2.2
• CS → P2.1
• CLK → P2.0