[Sipeed LicheeRV 86 Panel Review] 4-Transplanting lvgl-Adding touch control

manhuami2007

[Sipeed LicheeRV 86 Panel Review] 4-Transplanting lvgl-Adding touch control [Copy link]

 

In the previous review, we implemented the transplantation of lvgl, and we can add controls to change the display function. But how can a touchpad be without the touch function? Therefore, we need to add touch capabilities to lvgl in this review.

1. Check the touch device of the development board

There are three input devices listed in the /dev/input directory on the LicheeRV 86 development board . After testing, event2 is a touch screen device. As shown in the figure below, use ls /dev/inputthe input device hexdump /dev/input/eventto view the data generated by each touch.

You can also use geteventnaming to view the data of input devices. From the figure below, you can see that event2 corresponds to touch, event1 corresponds to audio input, and event0 corresponds to keyboard.

You can also view the input device information in the directory /proc/bus/input .

Through the above operations, we can know that the touchpad of the development board is /dev/input/event2 , and its corresponding handler is evdev.

2. Add touch function in lvgl

There is only one place that needs to be modified, which is lv_drv_conf.h . Add the touch screen as an input device in this file.

Through the first step, we know that the handler is evdev, so in lv_drv_conf.h ,USE_EVDEV it is set EVDEV_NAMEto /dev/input/event2.

Now you can use the touch screen on the LicheeRV 86 development board. Since the project is too large, I will not re-upload it. You can use the project I shared in the resource center, and then follow the second step to modify it and you can use it.

3. Touch Effects

The effect is as follows. When a key is pressed, the name of the key will change.