transmit status register
| RQCP0 | RQCP0 |
| TXOK0 | TXOK0 |
| ALST0 | ALST0 |
| TERR0 | TERR0 |
| ABRQ0 | ABRQ0 |
| RQCP1 | RQCP1 |
| TXOK1 | TXOK1 |
| ALST1 | ALST1 |
| TERR1 | TERR1 |
| ABRQ1 | ABRQ1 |
| RQCP2 | RQCP2 |
| TXOK2 | TXOK2 |
| ALST2 | ALST2 |
| TERR2 | TERR2 |
| ABRQ2 | ABRQ2 |
| CODE | CODE |
| TME0 | Lowest priority flag for mailbox 0 |
| TME1 | Lowest priority flag for mailbox 1 |
| TME2 | Lowest priority flag for mailbox 2 |
| LOW0 | Lowest priority flag for mailbox 0 |
| LOW1 | Lowest priority flag for mailbox 1 |
| LOW2 | Lowest priority flag for mailbox 2 |