Power management register.
| EN_SUSPENDM | Enable SUSPENDM signal. |
| SUSPEND | Suspend mode detected. |
| RESUME | Generate resume signaling. |
| RESET | Bus reset detected. |
| HS_MODE | High-speed mode detected. |
| HS_ENABLE | High-speed mode enable. |
| SOFTCONN | Softconn. |
| ISO_UPDATE | Wait for SOF during Isochronous xfers. |