SRD=value1, XN=value1
MPU Region Attribute and Size Register A3
| ENABLE | Region enable bit. |
| SIZE | MPU protection region size |
| SRD | Subregion disable bits 0 (value1): corresponding sub-region is enabled 1 (value2): corresponding sub-region is disabled |
| B | Memory access attribute |
| C | Memory access attribute |
| S | Shareable bit |
| TEX | Memory access attribute |
| AP | Access permission field |
| XN | Instruction access disable bit 0 (value1): instruction fetches enabled 1 (value2): instruction fetches disabled. |