Arduino connected to MAX7219

Arduino DS1307 RTC Clock with MAX7219 LED Display Controller

by Lewis Loflin


YouTube video for this project: Arduino DS1307 RTC Clock with MAX7219 LED Display Controller

Date: Nov 15, 2013. In this project I make use of Ds1307 real time clock chip and a MAX7219 Serially Interfaced 8-Digit LED Display to build a clock. The clock will display hours, minutes, and seconds and through the use of three switches one can set the time.

This is an updated version of a clock routine written in 2009 that only used the Arduino compiler serial monitor. I've added an additional connection to data pin 2 on the Arduino to the 1 Hz output of the Ds1307 . By the use of polling DP2 the time is updated every second to the display controller and the DP13 LED state is toggled creating a visual indication.

The code was ported over from the old clock demo while the routines to operate the MAX7219 were developed and ported over from a PIC18F2550 project. While the clock data is read using I2C is already BCD as used by the MAX7219, the routines handling the output had to be totally rewritten.

Arduino code for this project: arduino_max7219b.txt

While all three programs share things in common, none are alike. The 8-digit display module was purchased off of Ebay.

See the Arduino DS1307 schematic.