System bus mode register
| FB | Fixed Burst Length |
| BLEN4 | AXI Burst Length 4 |
| BLEN8 | AXI Burst Length 8 |
| BLEN16 | AXI Burst Length 16 |
| BLEN32 | AXI Burst Length 32 |
| BLEN64 | AXI Burst Length 64 |
| BLEN128 | AXI Burst Length 128 |
| BLEN256 | AXI Burst Length 256 |
| AALE | Automatic AXI LPI enable |
| AAL | Address-Aligned Beats |
| ONEKBBE | 1 Kbyte Boundary Crossing Enable for the AXI Master |
| RD_OSR_LMT | AXI Maximum Read Outstanding Request Limit |
| WR_OSR_LMT | AXI Maximum Write Outstanding Request Limit |
| LPI_XIT_PKT | Unlock on Magic Packet or Remote wake-up packet |
| EN_LPI | Enable Low Power Interface (LPI) |