I see. It's my understanding. I think PORTA has 18 pins, so the PCR of PORTB_0 should be 19, but in fact, the PCR value is calculated according to the maximum 32 per PORT group, PORTA occupies 0-32, PORTB_0 should start from 33.
However, when I checked the section on the number of PORT pins in the RM manual, there seemed to be no clear mark indicating that I should calculate according to the absence of 32 pins in the PORT group. Could you tell me where in the manual to get this information?