Asprogrammer+21013 <Trusted - Cheat Sheet>

ASProgrammer is a lightweight, powerful flashing utility written by npro. It was designed to replace the archaic Chinese software (often named CH341A.exe or NeoProgrammer) that typically comes with CH341A-based programmers.

The CH21013 is essentially a refined CH341A board. It typically features: asprogrammer+21013

Warning: The original CH341A outputs 5V on its I/O pins. Many CH21013 variants fix this with level shifters, but always verify your board. Feeding 5V to a 3.3V Winbond chip is a quick way to let the magic smoke out. Warning: The original CH341A outputs 5V on its I/O pins

Download Zadig (version 2.8 or later). Ensure your CH341A is plugged in. Why WinUSB

Why WinUSB? Unlike libusb, WinUSB has better timeout handling, directly solving the 21013 sync errors.