44.4.1.10 USB Status Register
Note: The U1STAT register is a window into a 4 byte FIFO
maintained by the USB OTG module. U1STAT value is only valid when the TRNIF bit
(U1IR[3]) is active. Clearing the TRNIF bit (U1IR[3]) advances the FIFO. Data in
register is invalid when the TRNIF bit (U1IR[3]) = 0.
| Name: | USTAT |
| Offset: | 0x4240 |
| Reset: | 0x0 |
| Property: | - |
| Bit | 31 | 30 | 29 | 28 | 27 | 26 | 25 | 24 | |
| Access | |||||||||
| Reset |
| Bit | 23 | 22 | 21 | 20 | 19 | 18 | 17 | 16 | |
| Access | |||||||||
| Reset |
| Bit | 15 | 14 | 13 | 12 | 11 | 10 | 9 | 8 | |
| Access | |||||||||
| Reset |
| Bit | 7 | 6 | 5 | 4 | 3 | 2 | 1 | 0 | |
| ENDPT[3:0] | DIR | PPBI | |||||||
| Access | R | R | R | R | R | R | |||
| Reset | x | x | x | x | x | x | |||
Bits 7:4 – ENDPT[3:0] Encoded Number of Last Endpoint Activity bits
| Value | Description |
|---|---|
| 1111 | Endpoint 15 |
| 1110 | Endpoint 14 |
| ... | |
| 0001 | Endpoint 1 |
| 0000 | Endpoint 0 |
Bit 3 – DIR Last BD Direction Indicator bit
| Value | Description |
|---|---|
| 1 | Last transaction was a TX |
| 0 | Last transaction was a RX |
Bit 2 – PPBI Ping-pong BD Pointer Indicator bit
| Value | Description |
|---|---|
| 1 | Last transaction was to the ODD BD bank |
| 0 | Last transaction was to the EVEN BD bank |