It may be best here to start with a known application from the SDK which uses the PUART, then modify it to fit your application.
Two examples we provide are puart_control and uart_firmware_upgrade.
1. Please confirm that you are modifying blecen.c
2. If you have modified this code, then it won’t change anything.
3. This code is in the ROM and is provided for reference.
4. Any code that you modify outside of the <SDK>/Apps directory will not work
Thank you for the detailed answer.
Now I know can't modify code outside of the <SDK>/Apps directory , because it in ROM .