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Pin Configuration

The MAX7219 has a total of 24 pins. Out of these, 8 are digit pins (labeled DIG0 to DIG7) and 8 are segment pins (labeled SEG A to SEG G and DP). The remaining pins are used for power and communication.

MAX7219 Pin Configuration

Note: If you read the datasheet, you will also see another chip called MAX7221 mentioned. It is nearly identical to the MAX7219, the main difference is that the MAX7221 supports standard SPI™, QSPI™, and MICROWIRE™ interfaces.

Communication Pins

These four pins are used for serial communication between the microcontroller and the MAX7219:

  • DIN (Data In): We use this pin to send display data to the MAX7219. Whatever we want to show on the LEDs is sent here from the microcontroller.

  • CLK (Clock): This pin provides the clock signal that controls the timing of data transfer.

  • LOAD (Chip Select): Also labeled CS on the MAX7221, this pin tells the chip when to take in the received data and update the display.

  • DOUT (Data Out): If we connect more than one MAX7219 in a chain (called a daisy-chain), this pin passes the data to the next chip. It should be connected to the DIN pin of the next MAX7219 module.