.. note::

    Hello, welcome to the SunFounder Raspberry Pi & Arduino & ESP32 Enthusiasts Community on Facebook! Dive deeper into Raspberry Pi, Arduino, and ESP32 with fellow enthusiasts.

    **Why Join?**

    - **Expert Support**: Solve post-sale issues and technical challenges with help from our community and team.
    - **Learn & Share**: Exchange tips and tutorials to enhance your skills.
    - **Exclusive Previews**: Get early access to new product announcements and sneak peeks.
    - **Special Discounts**: Enjoy exclusive discounts on our newest products.
    - **Festive Promotions and Giveaways**: Take part in giveaways and holiday promotions.

    👉 Ready to explore and create with us? Click [|link_sf_facebook|] and join today!

.. _cpn_led_matrix:

LED Dot Matrix
======================

.. image:: img/matrix_pic.png
    :width: 300

The LED dot matrix can be divided into two types: **Common Cathode (CC)** and **Common Anode (CA)**.  
They look similar on the outside, but their internal electrical structure is different.

The LED dot matrix used in this kit is a **Common Anode (CA)** type.  
You can identify it by the marking **“788BS”** printed on the side of the module.

Pin Layout
--------------------

The pins are located on both sides of the back of the module.  
When facing the side with the label:

* Pins **1–8** are on one side  
* Pins **9–16** are on the opposite side  

External view:

.. image:: img/matrix_pin.png

Internal Structure
-----------------------

The following figure shows the internal structure of the LED dot matrix.

* In a **Common Anode (CA)** matrix, **ROW = Anode** and **COL = Cathode**
* In a **Common Cathode (CC)** matrix, **ROW = Cathode** and **COL = Anode**

.. image:: img/matrix_internal.png
   :width: 400
   :align: center

For both CA and CC types, the physical pin positions for rows and columns are the same — only the electrical polarity is different.

Pin Mapping
-----------------------

.. list-table::
   :header-rows: 2
   :align: center

   * - **COL**
     - **1**
     - **2**
     - **3**
     - **4**
     - **5**
     - **6**
     - **7**
     - **8**
   * - **Pin No.**
     - **13**
     - **3**
     - **4**
     - **10**
     - **6**
     - **11**
     - **15**
     - **16**
   * - **ROW**
     - **1**
     - **2**
     - **3**
     - **4**
     - **5**
     - **6**
     - **7**
     - **8**
   * - **Pin No.**
     - **9**
     - **14**
     - **8**
     - **12**
     - **1**
     - **7**
     - **2**
     - **5**

How LEDs Are Turned On
----------------------------

To control a single LED, you must activate its **ROW** and **COL** pins correctly.

*Example: top-left LED (ROW 1, COL 1)*

- **CA type**  
  Set **ROW pin 9 = High**, **COL pin 13 = Low**

- **CC type**  
  Set **COL pin 13 = High**, **ROW pin 9 = Low**

*Example: light up the entire first column*

- **CA type**  
  Set **COL pin 13 = Low**  
  Set **ROW pins 9, 14, 8, 12, 1, 7, 2, 5 = High**

- **CC type**  
  Set **COL pin 13 = High**  
  Set **ROW pins 9, 14, 8, 12, 1, 7, 2, 5 = Low**

This row-column scanning method allows you to control each LED individually using multiplexing.