The parameter item "Self-study Companion" needs to display the clock on the LCD, and consider transplanting LVGL.After checking some information, the LVGL ecology is still good, but its power means porting, and application development will not be easy; in addition, lvgl is developing rapidly, thinking that the differences in the versions of various tutorials you find may not work if you integrate them together.The easiest way is to stand on the shoulders of predecessors, and copy the lvgl (seems to be the latest master branch) module (file) of the same hardware platform on the handle to your own project, and then modify the project accordingly.Because the transplant operation is bypassed, the happy path is the most convenient.

Maybe someone will raise the bar, so why not start directly from that lvgl routine?Because lvgl is only for display, not the core of scene business logic, so my base project can be the basic front and back main loop, or it can be the structure of rtos: here I take out the lvgl module, make the smallest changes, and put it where it is needed, to quickly verify porting, as a convenient starting point.

1. File copy, project configuration

Base project:

CH32V307VCT6_test is the project that prints cyclically

lvgl project:

01.lvgl_v8.2_for_ch32v_evb_TencentOS-tiny, transplant a new version of lvgl project

1) File Copy

2) Engineering configuration

This version of lvgl only needs to add its parent directory, and it handles relative paths internally.Unlike previous versions.

2. lvgl module initialization and operation

1) lvglv related initialization

lvgl can also be understood as an os-like framework on top of os that handles ui interaction, with its own heartbeat, input and output processing.Initialization includes the initialization of the framework and the initialization of dependent hardware drivers.

Initialize in a suitable place, if it is a bare project main is a good place, need to include the associated header file.

The parameter 1 of lv_tick_inc(1) is called once every 1ms to give lvgl heartbeat; lv_timer_handler() is because this example is for timer type, and the task handler entry is lv_timer_handler, which is used to respond to external input to lvgl.

2) example of lvgl task

This example copies the code of lvgl, and you can use gui-guider or other tool software to generate application code later.

From the code point of view, the display is a basic lv_obj_t object, lv_exmpale_meter_xxx initializes it, and builds a callback function set_value for external input control.

Operation and other

Other

The above is just the simplest transplant, lvgl still has many topics: file processing, input and output, external image import and so on.If transplanted to RTOS (such as TencentOS Tiny), the difference is the implementation of heartbeat, maybe use a tos timer, or calculate the tick difference in idle tasks?In addition, for the external input of lvgl, can you consider using a mailbox queue for processing?

Reference

1. TencentOS-Tiny's transplant LVGL v8.0.2 - Muzijian - Blog Park

2. AIoT Application Innovation Competition-Smart home control based on TencentOS Tiny

3. Qinheng CH32V307 application solution sharing of LVGL transplantation