====== lamaPLC: HT16K33 display controller ======
{{ :sensor:ht16k33_1.png?120|HT16K33 7-segment display}}
The **HT16K33** is a memory-mapped, multi-function LED controller driver. The device supports a maximum of 128 display segments (16 segments and 8 commons) and a 13×3 Maximum matrix key scan circuit. The software-configurable features of the HT16K33 make it suitable for a wide range of LED applications, including LED modules and display subsystems. The HT16K33 is compatible with most microcontrollers and communicates via a two-line bidirectional [[com:basic_i2c|I²C]] bus.

===== HT16K33 IC Feature =====  
  * Operating voltage: **4.5V–5.5V**
  * Integrated RC oscillator
  * I²C-bus interface
  * 16×8-bit RAM for display data storage
  * Max. 16×8 patterns, 16 segments, and eight commons
  * R/W address auto-increment
  * Max. 13×3 matrix key scanning
  * 16-step dimming circuit
  * Supports 20/24/28-pin SOP package types

|{{ :sensor:ht16k33_2.png?220|HT16K33 7-segment display}}|{{ :sensor:ht16k33_4.png?220|HT16K33 dot matrix display}}|{{ :sensor:ht16k33_5.png?220|HT16K33 dot matrix display}}|

===== I²C addressing ===== 
The base I²C address for an HT16K33 is **0x70**, but it can be changed to one of seven other addresses by setting the four address pins (**A0-A3**) via hardware. Each HT16K33 chip can have a unique address from **0x70** to **0x77**. If multiple HT16K33 devices are used on the same bus, each must have a distinct address, and if you use more than one, their addresses must be sequential, such as **0x70**, **0x71**, **0x72**. 

{{page>:tarhal}}

===== Schema =====
12*8 display application: (No INT pin function and 10*3 key function):
{{:sensor:ht16k33_3.png|12*8 display application: (No INT pin function and 10*3 key function)}}

 ===== 
==== Arduino Wiring Diagram  ====
The HT16K33 uses standard I²C pins. Connect your display as follows: 

^HT16K33 Pin^Arduino Uno Pin^Arduino Mega Pin^Description|
^VCC|5V|5V|Power (4.5V–5.5V)|
^GND|GND|GND|Ground|
^SDA|A4|20|Serial Data|
^SCL|A5|21|Serial Clock|

==== Required Libraries ====
 You will need two libraries from Adafruit: 
  * Adafruit LED Backpack Library
  * Adafruit GFX Library 

Install these via the Arduino Library Manager (//Tools > Manage Libraries...//). 

==== Arduino Example Code ====
This sketch demonstrates basic numeric display and colon control using the [[https://github.com/adafruit/Adafruit_LED_Backpack|Adafruit_LED_Backpack]] library.

<code c>
#include <Wire.h>
#include <Adafruit_GFX.h>
#include "Adafruit_LEDBackpack.h"

// Create the display object (Default I2C address is 0x70)
Adafruit_7segment matrix = Adafruit_7segment();

void setup() {
  matrix.begin(0x70);  // Initialize with I2C address
  matrix.setBrightness(10); // Set brightness from 0 to 15
}

void loop() {
  // 1. Display a whole number
  matrix.print(1234, DEC);
  matrix.writeDisplay();
  delay(2000);

  // 2. Display a floating point number
  matrix.print(12.34);
  matrix.writeDisplay();
  delay(2000);

  // 3. Simple Counter with blinking colon
  for (uint16_t counter = 0; counter < 100; counter++) {
    matrix.println(counter);
    matrix.drawColon(counter % 2 == 0); // Blink colon every other tick
    matrix.writeDisplay();
    delay(200);
  }
}
</code>


https://docs.arduino.cc/libraries/simple-ht16k33-library/


===== Sources =====
https://www.digikey.com/htmldatasheets/production/2070902/0/0/1/ht16k33.html

===== I²C topics on lamaPLC =====
{{topic>i2c}}

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