After finally taking a vacation, I decided to set up an E3 platform for fun. I wanted to turn it into a server while saving power during idle times. I found an ESP8266 (WeMos D1 R1) that had been collecting dust in my dev board collection, so I used it.
I wanted to make a low-power composite macro keyboard and mouse, and I set my eyes on the CH571 chip. I quickly got a development board to work with.
According to the datasheet, the Data area is divided into 16K+2K, which can be powered off at low voltage. Since the RV32 stack grows downward, the original linker script directly placed the stack bottom at the end of RAM, which couldn't meet the requirements.
This month I suddenly had the idea to make a keyboard and mouse simulator, so I went to the familiar WCH website and found the CH552G and CH340K.
Without further ado, let's get started. (At this time I didn't realize I was stepping into a big pit, because there's already a ready-made CH9326 chip)
As we all know, installing ESP-IDF on Windows is quite difficult with extremely slow compilation speed. Usually, compiling a HelloWorld program takes 5 minutes or more.
However, in practice, ESP-IDF on Linux (WSL) has extremely fast compilation speed. The same HelloWorld program can be compiled in just 10 seconds.