The CH55x Reset Controller is a one-touch solution for putting WCH CH554 and CH552 microcontrollers into bootloader mode. The reset controller performs a simple sequence to achieve this:

Disconnects both power and USB data lines from the devive Connects a 10k resistor from 3.3V to the D+ USB line Connects the power and USB data lines to the device After a short delay, disconnects the 10k resistor from the device

Notes:

This will only work with USB-powered CH55x devices, if the device has power from a battery or other power source, the CH55x will not reset Connect the computer to the 'DUT IN' micro USB port Connect your WCH CH55x device to the 'DUT OUT' USB A port This board was designed to work with 3.3V powered CH55x devices. It may work with 5V powered devices, but this is untested. The board includes a 'control in' connection for remotely controlling the bootloader sequence, however this is not supported in the software for the device.