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K230 Touch API Reference

Overview

The K230’s touch capabilities consist of two parts:

• Touch device management: dynamically register/delete touch devices through canmv_misc

• Touch read and write HAL: read touch point and device information through drv_touch instance

Related header files:

• src/rtsmart/libs/rtsmart_hal/components/canmv_misc/canmv_misc.h

• src/rtsmart/libs/rtsmart_hal/drivers/touch/drv_touch.h

Key data structures

struct drv_touch_config_t

Used to pass in hardware configuration when creating a touch device:

• touch_dev_index: device index

• range_x / range_y: coordinate range (0 can be left to the system default)

• pin_intr / intr_value: Interrupt pin and active level (available when no interrupt is available -1)

• pin_reset / reset_value: Reset pin and effective level (-1 is available when there is no reset)

• i2c_bus_index / i2c_bus_speed: I2C bus number and speed

struct drv_touch_data

Single touch point data:

• event: event type (NONE/UP/DOWN/MOVE)

• track_id: Contact tracing ID

• x_coordinate/y_coordinate: Contact coordinates

• width: contact width

• timestamp: timestamp

struct drv_touch_info

Device capability information:

• type: touch type

• vendor: Manufacturer information

• point_num: Maximum number of contacts

• range_x / range_y: coordinate range

Device Management API (canmv_misc)

canmv_misc_create_touch_device

int canmv_misc_create_touch_device(struct drv_touch_config_t* cfg);

Press cfg to register a touch device.

• Return value: 0 success, non-0 failure.

canmv_misc_delete_touch_device

int canmv_misc_delete_touch_device(int index);

Unregister touch device by index.

• Return value: 0 success, non-0 failure.

Read and write HAL API (drv_touch)

drv_touch_inst_create

int drv_touch_inst_create(int id, drv_touch_inst_t** inst);

Create a touch instance.

• Common errors: -1 parameter error, -2 device ID is invalid, -3 has insufficient memory.

drv_touch_inst_destroy

void drv_touch_inst_destroy(drv_touch_inst_t** inst);

Destroy the instance and release resources.

drv_touch_read

int drv_touch_read(drv_touch_inst_t* inst, struct drv_touch_data* touch_data, int max_points);

Read touch points.

• Return value: >0 represents the number of contacts, 0 has no event, <0 is an error (common -1/-2).

drv_touch_get_info

int drv_touch_get_info(drv_touch_inst_t* inst, struct drv_touch_info* info);

Query device capability information.

drv_touch_get_config

int drv_touch_get_config(drv_touch_inst_t* inst, struct drv_touch_config_t* cfg);

Query the current device configuration.

drv_touch_reset

int drv_touch_reset(drv_touch_inst_t* inst);

Perform a touch device reset.

drv_touch_get_default_rotate

int drv_touch_get_default_rotate(drv_touch_inst_t* inst, int* rotate);

Read the default rotation configuration (0/90/180/270/swap_xy).

Recommended calling process

1. If you need to dynamically create a device, call canmv_misc_create_touch_device() first.

2. Call drv_touch_inst_create() to open the instance.

3. First call drv_touch_get_info() / drv_touch_get_config() to confirm the capability and coordinate range.

4. Call drv_touch_read() cyclically to read contact events.

5. Call drv_touch_inst_destroy() on exit.

6. If it is a dynamically created device, canmv_misc_delete_touch_device() is called last.

Reference example

• src/rtsmart/examples/peripheral/touch/test_touch.c