Transmit FIFO status of Tx channel 0
| OUTFIFO_FULL_L1 | L1 Tx FIFO full signal for Tx channel 0. |
| OUTFIFO_EMPTY_L1 | L1 Tx FIFO empty signal for Tx channel 0. |
| OUTFIFO_FULL_L2 | L2 Tx FIFO full signal for Tx channel 0. |
| OUTFIFO_EMPTY_L2 | L2 Tx FIFO empty signal for Tx channel 0. |
| OUTFIFO_FULL_L3 | L3 Tx FIFO full signal for Tx channel 0. |
| OUTFIFO_EMPTY_L3 | L3 Tx FIFO empty signal for Tx channel 0. |
| OUTFIFO_CNT_L1 | The register stores the byte number of the data in L1 Tx FIFO for Tx channel 0. |
| OUTFIFO_CNT_L2 | The register stores the byte number of the data in L2 Tx FIFO for Tx channel 0. |
| OUTFIFO_CNT_L3 | The register stores the byte number of the data in L3 Tx FIFO for Tx channel 0. |
| OUT_REMAIN_UNDER_1B_L3 | reserved |
| OUT_REMAIN_UNDER_2B_L3 | reserved |
| OUT_REMAIN_UNDER_3B_L3 | reserved |
| OUT_REMAIN_UNDER_4B_L3 | reserved |