SPRUHM9H October 2014 – May 2024 TMS320F28075 , TMS320F28075-Q1 , TMS320F28076
The USB control and status endpoint 0 low 8-bit register (USBCSRL0) provides control and status bits for endpoint 0.
| Mode(s): | Host | Device |
USBCSRL0 in Host mode is shown in Figure 22-34 and described in Table 22-36.
| 7 | 6 | 5 | 4 | 3 | 2 | 1 | 0 |
| NAKTO | STATUS | REQPKT | ERROR | SETUP | STALLED | TXRDY | RXRDY |
| R/W-0 | R/W-0 | R/W-0 | R/W-0 | R/W-0 | R/W-0 | R/W-0 | R/W-0 |
| LEGEND: R/W = Read/Write; -n = value after reset |
| Bit | Field | Value | Description |
|---|---|---|---|
| 7 | NAKTO | NAK Timeout. Software must clear this bit to allow the endpoint to continue. | |
| 0 | No timeout | ||
| 1 | Indicates that endpoint 0 is halted following the receipt of NAK responses for longer than the time set by the USBNAKLMT register. | ||
| 6 | STATUS | Status Packet. Setting this bit ensures that the DT bit is set in the USBCSRH0 register so that a DATA1 packet is used for the STATUS stage transaction. | |
| 0 | No transaction | ||
| 1 | Initiates a STATUS stage transaction. This bit must be set at the same time as the TXRDY or REQPKT bit is set. | ||
| This bit is automatically cleared when the STATUS stage is over. | |||
| 5 | REQPKT | Request Packet. This bit is cleared when the RXRDY bit is set. | |
| 0 | No request | ||
| 1 | Requests an IN transaction. | ||
| 4 | ERROR | Error. Software must clear this bit. | |
| 0 | No error | ||
| 1 | Three attempts have been made to perform a transaction with no response from the peripheral. The EP0 bit in the USBTXIS register is also set in this situation. | ||
| 3 | SETUP | Setup Packet. Setting this bit always clears the DT bit in the USBCSRH0 register to send a DATA0 packet. | |
| 0 | Sends an OUT token. | ||
| 1 | Sends a SETUP token instead of an OUT token for the transaction. This bit should be set at the same time as the TXRDY bit is set. | ||
| 2 | STALLED | Endpoint Stalled. Software must clear this bit. | |
| 0 | No handshake has been received. | ||
| 1 | A STALL handshake has been received. | ||
| 1 | TXRDY | Transmit Packet Ready. If both the TXRDY and SETUP bits are set, a setup packet is sent. If just TXRDY is set, an OUT packet is sent. | |
| 0 | No transmit packet is ready. | ||
| 1 | Software sets this bit after loading a data packet into the TX FIFO. The EP0 bit in the USBTXIS register is also set in this situation. | ||
| 0 | RXRDY | Receive Packet Ready. Software must clear this bit after the packet has been read from the FIFO to acknowledge that the data has been read from the FIFO. | |
| 0 | No receive packet has been received. | ||
| 1 | Indicates that a data packet has been received in the RX FIFO. The EP0 bit in the USBTXIS register is also set in this situation. |
USBCSRL0 in Device mode is shown in Figure 22-35 and described in Table 22-37.
| 7 | 6 | 5 | 4 | 3 | 2 | 1 | 0 |
| SETENDC | RXRDYC | STALL | SETEND | DATAEND | STALLED | TXRDY | RXRDY |
| W1C-0 | W1C-0 | R/W-0 | R-0 | R/W-0 | R/W-0 | R/W-0 | R-0 |
| LEGEND: R/W = Read/Write; R = Read only; W = Write only; -n = value after reset |
| Bit | Field | Value | Description |
|---|---|---|---|
| 7 | SETENDC | Setup End Clear | |
| 0 | No effect | ||
| 1 | Writing a 1 to this bit clears the SETEND bit. | ||
| 6 | RXRDYC | RXRDY Clear | |
| 0 | No effect | ||
| 1 | Writing a 1 to this bit clears the RXRDY bit. | ||
| 5 | STALL | Send Stall. | |
| 0 | No effect | ||
| 1 | Terminates the current transaction and transmits the STALL handshake. | ||
| This bit is cleared automatically after the STALL handshake is transmitted. | |||
| 4 | SETEND | Setup end. | |
| 0 | A control transaction has not ended or ended after the DATAEND bit was set. | ||
| 1 | A control transaction has ended before the DATAEND bit has been set. The EP0 bit in the USBTXIS register is also set in this situation. | ||
| This bit is cleared by writing a 1 to the SETENDC bit. | |||
| 3 | DATAEND | Data end. | |
| 0 | No effect | ||
| 1 | Set this bit in the following situations:
| ||
| This bit is cleared automatically. | |||
| 2 | STALLED | Endpoint Stalled. Software must clear this bit. | |
| 0 | A STALL handshake has not been transmitted. | ||
| 1 | A STALL handshake has been transmitted. | ||
| 1 | TXRDY | Transmit Packet Ready. If both the TXRDY and SETUP bits are set, a setup packet is sent. If just TXRDY is set, an OUT packet is sent. | |
| 0 | No transmit packet is ready. | ||
| 1 | Software sets this bit after loading an IN data packet into the TX FIFO. The EP0 bit in the USBTXIS register is also set in this situation. | ||
| 0 | RXRDY | Receive Packet Ready. | |
| 0 | No receive packet has been received. | ||
| 1 | A data packet has been received. The EP0 bit in the USBTXIS register is also set in this situation. | ||
| This bit is cleared by writing a 1 to the RXRDYC bit. |