Baidu searched this APM's Arduino compiler, and I searched a lot, all of which require points.
Later, I found the official address. free download.
Go directly to the following link.
https://firmware.ardupilot.org/Tools/Arduino/
find the download package in the figure below and download it.
After downloading, refer to https://blog.csdn.net/u010682510/article/details/53019637?utm_medium=distribute.pc_relevant_download.none-task-blog-BlogCommendFromBaidu-2.nonecase&dist_request_id=f40ffd7a-9146-47f8-9e0b-de0f82b_1 utm_source=distribute.pc_relevant_download.none-task-blog-BlogCommendFromBaidu-2.nonecas to configure.
After configuration, the following problem may occur during compilation.
It will prompt the error programmer type must be written as "id_type".
At that time, the domestic website saw some people asking, but there was no answer. I went abroad and searched it. The answer is actually very simple.
Rename or delete the error file to compile.