MAX7219LED8x8

MAX7219Led8x8 is a C library for working with the MAX7219 display driver to control 8×8 LEDmatrix. It is intended to be used with the Tinusaur board but should also work with any other board based on ATtiny85 or similar microcontroller.

The MAX7219 is manufactured by Maxim Integrated is compact, serial input/output common-cathode display driver that could interface microcontrollers to 64 individual LEDs, 7-segment numeric LED displays of up to 8 digits, bar-graph displays, etc. Included on-chip are a BCD code-B decoder, multiplex scan circuitry, segment and digit drivers, and an 8×8 static RAM that stores each digit. Only one external resistor is required to set the segment current for all LEDs.

To put that in simpler words – with the MAX7219 driver it is possible to control 8×8 LED matrix using just 2 wires serial interface – one for the sync clock and one for the data. There is another wire that could be used to enable/disable the communication with the chip. The maximum frequency for the serial interface is 10MHz.

Working with MAX7219 is very simple – turning on and off individual LEDs is done by sending 2-bytes command to the driver containing the row and the byte which bits define which LED value to set.