USB2.0HUB based on SL2.1A

The project is relatively simple, so I won't describe it in detail. I'll just state a few notes:
1. You don't need to add the load capacitor next to the crystal oscillator
(the chip has an integrated 20pF load capacitor. Many open source projects here have problems, but adding it will not affect the stability. Please pay attention to the crystal oscillator selection)
(Image source: official website, but it is not mentioned in the manual, and the official case is not added)
 
2. SL2.1A does not recommend using a USB flash drive to transfer large amounts of data for a long time. It generates a lot of heat and may not be stable. Therefore, this design adds a heat sink,
but the transmission rate is still stable and meets the requirements.
 
3. The switch controls the opening and closing of the HUB, and four LEDs are connected in parallel. The panel design allows the board to be light-transmitting.
4. If you want to have channel insertion detection, you can use SL2.2s, which costs 2r, which is twice as expensive as this 1r, and you need to plug in an external EEPROM. I personally feel it is not cost-effective...