Overview
MAX7219 is an integrated serial input/output common-cathode display driver, which connects a microprocessor
and an 8-digit 7-segment digital LED display, and can also be connected to a bar graph display or 64 independent
LEDs. It includes an on-chip B-type BCD encoder, multiple scan loops, segment word drivers, and an 8*8 static
RAM to store each data. Only one external register is used to set the segment current of each LED. A convenient
four-wire serial interface can be connected to all general-purpose microprocessors. Each data can be
addressed without rewriting all the displays when updating. MAX7219 also allows users to select encoding
or not encoding for each data. The entire device includes a 150μA low-power shutdown mode, analog
and digital brightness control, a scan limit register allowing users to display 1-8 bits of data, and a
detection mode to make all LEDs glow.
3. When multiple modules are cascaded, the input terminal of the first module is connected to the CPU,
the output terminal is connected to the input terminal of the second module, the output terminal of the second
module is connected to the input terminal of the third module, and so on.