K230 TOUCH Usage Guide#

Overview#

The K230 supports both capacitive and resistive touch input, providing a TOUCH class interface based on the RT-Smart framework. Developers can use it to read touch point coordinates, event types, and more, suitable for HMI, interactive terminals, and similar scenarios.

Quick Start Example#

The following example demonstrates how to read touch point data from the screen:

from machine import TOUCH

# Instantiate default touch device 0
tp = TOUCH(0)

# Read current touch point data (returns a tuple of TOUCH_INFO objects)
p = tp.read()
print(p)

# If there are touch points, access the first point's coordinates and event type
# print(p[0].x)       # X coordinate
# print(p[0].y)       # Y coordinate
# print(p[0].event)   # Event type (e.g. EVENT_DOWN, EVENT_MOVE, EVENT_UP)

API Overview#

API	Description
`TOUCH(dev, *, rotate=-1, range_x=-1, range_y=-1, i2c=None, rst=None, int=None)`	Create a touch instance. `dev=0` for system default, `dev!=0` for custom device. See below for parameters.
`read([count])`	Returns current touch point info as a tuple of TOUCH_INFO objects. `count` is the max number of points to read (default 1).
`deinit()`	Release touch resources.

Constructor Parameters#

dev: Touch device index. 0 for system default, non-0 for custom device.
rotate: Coordinate rotation, see Constants, default -1 (use device default).
range_x, range_y: Only valid for custom devices, specify touch screen resolution.
i2c: Only valid for custom devices, I2C bus object, required.
rst, int: Only valid for custom devices, reset/interrupt pin objects, optional.
Other parameters (e.g. type, slave_addr) are deprecated.

TOUCH_INFO Object Attributes#

event: Event code, see Constants
track_id: Touch point ID
width: Touch point width
x: X coordinate
y: Y coordinate
timestamp: Timestamp

Example Details#

1. Instantiate Device#

# System default touch
tp = TOUCH(0)

# Custom touch device (must specify i2c, resolution, etc.)
# tp = TOUCH(1, i2c=my_i2c, range_x=800, range_y=480)

2. Read Touch Data#

p = tp.read()
print(p)

The returned p is a tuple, each element is a TOUCH_INFO object. Each object contains:

x: X coordinate
y: Y coordinate
event: Touch event (e.g. EVENT_DOWN, EVENT_MOVE, EVENT_UP)
track_id, width, timestamp, etc.

3. Example Output#

(<TOUCH_INFO x=120 y=65 event=0 ...>,)

If there are multiple touch points (multi-touch):

(<TOUCH_INFO x=120 y=65 event=0 ...>, <TOUCH_INFO x=250 y=130 event=0 ...>)

Constants#

Touch Events#

TOUCH.EVENT_NONE: No event
TOUCH.EVENT_UP: Released
TOUCH.EVENT_DOWN: Pressed
TOUCH.EVENT_MOVE: Moved

Coordinate Rotation#

TOUCH.ROTATE_0: No rotation
TOUCH.ROTATE_90: Rotate 90 degrees
TOUCH.ROTATE_180: Rotate 180 degrees
TOUCH.ROTATE_270: Rotate 270 degrees
TOUCH.ROTATE_SWAP_XY: Swap X and Y

Touch Types (compatibility only, all values are 0)#

TOUCH.TYPE_CST226SE
TOUCH.TYPE_CST328
TOUCH.TYPE_GT911

FAQ#

Q: No touch points are read, returns an empty tuple? A: This means the screen is not being touched. tp.read() only returns points when the screen is pressed.

Q: How to handle multi-touch? A: The result is a tuple of TOUCH_INFO objects, use a for loop to iterate through them.

Q: Is coordinate rotation supported? A: Yes, use the rotate parameter (e.g. TOUCH.ROTATE_90) to enable coordinate rotation.

K230 TOUCH Usage Guide

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