Thursday, January 15, 2015

How to identify pin 1 of 8x8 LED Matrix

This post show how to identify pin 1, and pin 16, of 8x8 LED Matrix.

Part I: Row Anode Column Cathode 8x8 LED Matrix, 1588BS as example. Current flow from pin 1 to pin 16 to make LED on row 5 col 8 ON.

Use the example of Row-Column Scanning an 8x8 LED matrix to show it work.

The connection between Arduino Uno and 8x8 LED Matrix is show here:

(It's recommended to add 220 ohm resisters to limit the current)

We need a test program to verify our connection, visit, copy the example sketch of Walking bit on 8*8 LED Matrix, and download to Arduino Uno.

If your 8x8 LED Matrix have no marking for pin 1, we can use a multimeter to identify pin 1, and also pin 16.

This scheme diagram show when we apply +ve on pin 1 and -ve on pin 16, the LED on row 5 col 8 will be turn on.

Switch multimeter to diode test, the red lead will be +ve and black lead will be -ve.

Refer to the below video:
There are 4 possibility of pin 1 and 16, only one case will turn on a LED. When the LED (row 5 col 8) on, the pin connected to the RED lead of multimeter is pin 1.

Part II: Row Cathode Column Anode 8x8 LED Matrix, 1088AS as example. Current flow from pin 16 to pin 1 to make LED on row 5 col 8 ON.

Same procedure as in part I, with pin 1 on BLACK lead of multimeter.

Working example, refer to next post "Arduino Uno + SPI 8x8 LED Matrix, with MAX7219 LED driver".

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