I was curious to play with the CH552 MCU, so I made this board:

So far I have never used an 8051 core, so this seemed like a good opportunity to try it out.
All the details here: 
https://hackaday.io/project/169671Here there are some CH552 key data:
    8051 core with most standard registers, commands etc. (8x-15x faster than the original core);
    Integrated oscillator;
    USB 2.0 Full Speed;
    USB-C support;
    2x UART
    3x timer;
    2x 8bit PWM;
    1x SPI master / slave;
    4x ADC 8bit input;
    6x touch input;
    16KB Fash;
    1KB xRAM;
    256B iRAM;