USB to 4-port serial TTL downloader with no cold start

I. Product Introduction:
This USB-to-4-port serial programmer, built using CH344, has been tested and can download STC series microcontrollers, including the ESP32 microcontroller. For the ESP32 microcontroller, the factory mode of the official flash_download_tool allows simultaneous downloading to multiple devices.
II. Circuit Design
: The cold-start circuit uses a transistor and PMOS configuration. During programming, the RTS pin is pulled low, interrupting the 5V power supply for several hundred milliseconds. The circuit diagram uses 1uF pins (C1, C2, C3, C4), which is sufficient for programming STC microcontrollers. My actual prototype test circuit used 10uF, resulting in a longer 5V interruption time compared to 1uF.
III. Discussion
1. The programming interface can be modified according to your usage. If using 3.3V, add an AMS1117-3.3 to convert the power supply. CH344 supports 3.3V and 5V.
2. Programming ESP32 requires grounding GPIO00 to put the module in download mode. To ensure compatibility with STC microcontrollers, I did not directly implement the GPIO00 pin pull-down circuit on the programmer. You can modify it as needed.
3. The CH344's CFG pin, the manual says, can be set to enable or disable flow control. I have reserved the interface, but I don't know the specific usage. It seems there's no difference between CFG being grounded and floating. Discussion on the usage of CFG is welcome.