Hello Yangyue,
In your screenshot, the MCU is set as LPC824. While your target is LPC845? Please change it to the right target.

I am not sure of J-Flash v6.20 support LPC845. But I use J-Flash v6.4, it can support LPC845 without problem.

Please make sure you have board successfully connected before program/erase.

Have a great day,
Jun Zhang
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