Port bit reset register
| IOCB0 | Clear bit 0 |
| IOCB1 | Clear bit 1 |
| IOCB2 | Clear bit 1 |
| IOCB3 | Clear bit 3 |
| IOCB4 | Clear bit 4 |
| IOCB5 | Clear bit 5 |
| IOCB6 | Clear bit 6 |
| IOCB7 | Clear bit 7 |
| IOCB8 | Clear bit 8 |
| IOCB9 | Clear bit 9 |
| IOCB10 | Clear bit 10 |
| IOCB11 | Clear bit 11 |
| IOCB12 | Clear bit 12 |
| IOCB13 | Clear bit 13 |
| IOCB14 | Clear bit 14 |
| IOCB15 | Clear bit 15 |