Circuit to Control 16*8 LED Matrix Using Arduino Mega and 74595 (Part 1 of 13)

Previous:  Circuit for Cascade Operation of Two 74595

          Before start reading this tutorial, please read Cascade Operation of Two 74595 Shift Registers using Arduino Mega.

          Here, we will cascade two 74595 ICs for controlling two 8*8 LED matrices. LED matrices are arranged in such a way that control pins of LED matrices should be at the top and bottom of the LED matrix as shown in the following image. To avoid confusion in fixing LED matrices, note the position of wedges at the middle of sides of each LED matrices.

          An individual LED matrix is shown below. Each LED matrix have 16 control pins of which eight are anode pins (16, 15, 11, 3, 10, 5, 6, 13) and remaining are cathode pins (4, 7, 2, 8, 12, 1, 14, 9).

          Internal circuit of an 8*8 LED matrix is given below. 64 LEDs are arranged to form 8 rows and 8 columns. One anode pin will be common for eight LEDs. Similarly, one cathode pin will be common for eight LEDs.

          Three 74595 ICs are used in the circuit of which two ICs are cascade connected. Pin out diagram of 74595 is given below.

          Circuit diagram to control two 8*8 LED matrix using Arduino mega and 74595 is given below. Cascade connected ICs are used for controlling the anode pins of 8*8 LED matrices. Cathode pins of both LED matrices are shorted. These shorted cathode pins are then connected to the Q0-Q7 pins of other 74595 as shown in the circuit diagram. If the circuit is not clear, download it to your computer (Right click on the circuit => Save image as) and open in a suitable image viewer.

Continued in next page (Part 2)