Hi @JinHan ,
While using a custom PCB, please make sure that your board matches the conditions of the programming pin and power pin connections.
For Programming Pin Connections, please refer to the Hardware Connections section in the PSoC® 5LP Device Programming Specifications, and for Power Pin Connections, please refer to the PSoC Power Pin Connections sections in the PSoC 3 and PSoC 5LP Hardware Design Considerations.
Kindly verify and ensure that it follows the pin connection instructions.
In PSoC Programmer window, choose Reset mode instead of Power Cycle.