JlinkV9+6Mbps hardware serial port

The original post refers to ShouGongFan https://oshwhub.com/nokia82/jlink_v9-5-cp2102.
 
Some things have been modified on its basis:
    1. Modify the power supply mode. The original STM32F205 was powered by CP2102, and now it is powered by a separate LDO. In addition, a separate LDO is added to power the development board, etc.
    2. Modify the serial port chip from the original CP2102 to CH343, which can reach the hardware 6Mbps rate. It has been tested with STM32F4 and works perfectly.
    3. From the original EasyEDA professional version, it was redrawn to the EasyEDA ordinary version.
 
Some points to note:
    1. The Jlink driver version should not be too high. I use V6.44 without reporting pirated versions. I have tested V7.0 and some versions above, and all reported pirated versions.
    2. Because the serial port communication rate is too fast, it may happen that the debugged device has been sending data to CH343 at a high rate just after power on, occupying the USB bandwidth and thus failing to connect to Jlink. The solution is to connect the serial line (unplug the Dupont line first) to Jlink with Jlink Command and then plug the serial line back in.
 
This debugger is very powerful and is perfectly suitable for motor debugging, power supply, inverter, etc. It can directly use DMA to send serial data in PWM interrupt to observe the board status.
In addition, STM32F4 can reach 6Mbps (I use STM32F400, 100M main frequency), and the low-end ones are unlikely to reach that.