.. _arduino_touch:

==================
1.8 Touch Panel
==================

Read touch coordinates from the FT6336U capacitive touch controller over I2C.

Overview
========

This example shows how to read multi-touch data from the FT6336U capacitive touch panel controller. On startup, it dumps the main configuration registers for debugging, then continuously scans for up to 2 simultaneous touch points.

.. note::
   This example is based on the open-source ``ScanMultiTouch`` example from the Arduino-FT6336U library. For the LAFVIN ESP32-S3 Multimedia Kit, we adapted the I2C and touch-controller pin configuration, kept the multi-touch scanning behavior, and simplified the serial output so the results are easier to read during learning and demonstration.

What You'll Learn
=================

* Initializing the FT6336U touch controller over I2C
* Reading device configuration registers
* Detecting touch points and reading X/Y coordinates
* Understanding I2C device addressing

Before You Begin
================

Complete the setup steps in :ref:`preparation` before continuing.

.. note::
   Use the recommended Arduino IDE settings in :ref:`arduino_board_settings` unless this lesson says otherwise.

Open the example sketch from the code package:

``LAFVIN-ESP32-S3-Multimedia-Kit-main/1.Arduino/8.Touch/8.Touch.ino``

This example uses the **onboard** touch panel. No external wiring is required.

======== ========
Signal   ESP32-S3
======== ========
SDA      GPIO 2
SCL      GPIO 1
======== ========

Upload and Test
===============

#. Connect the board with a USB Type-C data cable.
#. Open ``8.Touch.ino`` in Arduino IDE.
#. In the **Tools** menu, select ``ESP32S3 Dev Module`` as the board and choose the correct serial port.
#. Click **Upload**.
#. Open **Serial Monitor** at ``115200`` baud. On startup, the sketch prints the FT6336U configuration registers::

      FT6336U Device Mode: 0x00
      FT6336U Threshold: 0x30
      ...
      Chip ID: 0x06
      Firmware ID: 0x05

#. Touch the screen. Coordinates appear in the Serial Monitor every 100 ms::

      FT6336U TD Count 1 / TD1 (1,  150,  200) / TD2 (0,    0,    0)

   The format is: touch status (1 = pressed), X coordinate, Y coordinate. The second touch point shows ``0`` when only one finger is touching.

How the Code Works
==================

**Sensor Initialization**

The FT6336U object is created with the board's I2C pins and with reset and interrupt pins disabled.

.. code-block:: cpp

   #define I2C_SDA 2
   #define I2C_SCL 1
   #define RST_N_PIN -1
   #define INT_N_PIN -1

   FT6336U ft6336u(I2C_SDA, I2C_SCL, RST_N_PIN, INT_N_PIN);

**Starting the Controller**

The sketch starts the touch controller in ``setup()`` before reading any status or touch data.

.. code-block:: cpp

   void setup() {
       Serial.begin(115200);

       ft6336u.begin();
   }

**Reading Registers**

On startup, the sketch reads the main FT6336U configuration registers and prints them to the Serial Monitor.

.. code-block:: cpp

      Serial.print("FT6336U Device Mode: ");
      Serial.println(ft6336u.read_device_mode());
      Serial.print("FT6336U Threshold: 0x");
      Serial.println(ft6336u.read_touch_threshold(), HEX);
      Serial.print("FT6336U Chip ID: 0x");
      Serial.println(ft6336u.read_chip_id(), HEX);
      Serial.print("FT6336U Firm ID: 0x");
      Serial.println(ft6336u.read_firmware_id(), HEX);

**Touch Scanning**

The ``scan()`` method returns up to two touch points, and the sketch prints their status and coordinates as one formatted line.

.. code-block:: cpp

   tp = ft6336u.scan();
   char tempString[128];
   sprintf(tempString, "FT6336U TD Count %d / TD1 (%d, %4d, %4d) / TD2 (%d, %4d, %4d)",
       tp.touch_count, tp.tp[0].status, tp.tp[0].x, tp.tp[0].y,
       tp.tp[1].status, tp.tp[1].x, tp.tp[1].y);
   Serial.println(tempString);
   delay(100);

In the provided sketch:

* The register dump includes the main FT6336U configuration and identification values
* Touch scanning runs at 100 ms intervals, which is enough for a simple serial demonstration
* Coordinates are reported in the display's native coordinate space

Try This Next
=============

* Reduce the scan interval from 100 ms to 20 ms for more responsive touch updates
* Experiment with the touch threshold register to change panel sensitivity
* Use the touch coordinates as input for your own projects, such as drawing or button control