K230 Touch Screen (TOUCH) Usage Tutorial#

Overview#

K230 supports touch input for both capacitive screens and resistive screens, providing a TOUCH class interface based on the RT-Smart package. Developers can use it to read touch point coordinates, event types, and other information, making it widely applicable in scenarios such as HMI and interactive terminals.

Quick Start Example#

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

from machine import TOUCH

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

# Read current touch point data (returns a tuple, each element is a TOUCH_INFO object)
p = tp.read()
print(p)

# If there are touch points, you can access the coordinates and event type of the first touch point
# 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)

Interface Description#

Interface Name	Description
`TOUCH(dev, *, rotate=-1, range_x=-1, range_y=-1, i2c=None, rst=None, int=None)`	Creates a touch screen instance, `dev=0` indicates the system default, `dev!=0` is a custom device, see parameter details below
`read([count])`	Returns current touch point information, returns a tuple where each element is a TOUCH_INFO object, `count` is the maximum number of touch points to read (default 1)
`deinit()`	Releases touch resources

Constructor Parameter Description#

dev: Touch device number, 0 for system default, non-zero for custom device.
rotate: Coordinate rotation, see Constants, default -1 (use device default).
range_x, range_y: Valid only for custom devices, specifies the touch screen resolution.
i2c: Valid only for custom devices, I2C bus object, required.
rst, int: Valid only for custom devices, reset/interrupt pin objects, optional.
Other parameters are deprecated.

TOUCH_INFO Object Properties#

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

Detailed Examples#

Instantiating the Device#

# System default touch
tp = TOUCH(0)

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

Reading Touch Data#

p = tp.read()
print(p)

The returned p is a tuple, where 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.

Example Output Reference#

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

If there are multiple touch points, e.g., supporting multi-finger operation:

(<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: Lift up
TOUCH.EVENT_DOWN: Press down
TOUCH.EVENT_MOVE: Move

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: XY swap

Touch Types (reserved for compatibility, actual values are all 0)#

TOUCH.TYPE_CST226SE
TOUCH.TYPE_CST328
TOUCH.TYPE_GT911

Application Scenarios#

Scenario	Example
GUI Interaction	Button clicks and slide toggles driven by touch points
Custom Gesture Recognition	Multi-point sliding, rotation and other gesture recognition
Simple Drawing Board or Signature Pad	Line drawing based on touch point trajectories

Frequently Asked Questions#

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

Q: How to handle multi-touch? A: The read result is a tuple containing multiple TOUCH_INFO entries. Use a for loop to iterate through them.

Q: Does it support coordinate rotation? A: Yes, coordinate rotation can be enabled through the rotate parameter (such as TOUCH.ROTATE_90).

K230 Touch Screen (TOUCH) Usage Tutorial

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