Flash control register
| PG | Programming |
| PER | Page erase |
| MER | Mass erase |
| OPTPG | Option byte programming |
| OPTER | Option byte erase |
| STRT | Start |
| LOCK | Lock |
| OPTWRE | Option bytes write enable |
| ERRIE | Error interrupt enable |
| EOPIE | End of operation interrupt enable |
| FORCE_OPTLOAD | Force option byte loading |