Kenji rewrote the ISR. Instead of fixed delays, the PIC would measure the round-trip time of a dummy command at startup, then adjust its turnaround window based on the actual latency of the host USB stack. He added a small state machine to handle retries gracefully when collisions happened.
: When connected, Windows typically identifies the device as "USB-SERIAL CH340K (COMx)" in the Device Manager. Driver Requirements Ld-c101 Usb To Ci-v Driver
: For the most up-to-date CH340 drivers , users often go directly to the manufacturer, WCH (Jiangsu Qinheng Microelectronics) . Kenji rewrote the ISR