USB Registers
1754
SLAU723A – October 2017 – Revised October 2018
Copyright © 2017–2018, Texas Instruments Incorporated
Universal Serial Bus (USB) Controller
Table 27-58. USBRXCSRLn Register Field Descriptions (OTG B / Device) (continued)
Bit
Field
Type
Reset
Description
4
FLUSH
R/W
0x0
Flush FIFO.
The CPU writes a 1 to this bit to flush the next packet to be read
from the endpoint receive FIFO. The FIFO pointer is reset and the
RXRDY bit is cleared.
Note that if the FIFO is double-buffered, FLUSH may have to be set
twice to completely clear the FIFO.
This bit should only be set when the RXRDY bit is set. At other
times, it may cause data to be corrupted.
0x0 = No effect.
0x1 = Flushes the next packet from the endpoint receive FIFO. The
FIFO pointer is reset and the RXRDY bit is cleared.
3
DATAERR
R
0x0
Data Error.
This bit is cleared when RXRDY is cleared.
This bit is only valid when the endpoint is operating in Isochronous
mode. In Bulk mode, it always returns zero.
0x0 = Normal operation.
0x1 = Indicates that RXRDY is set and the data packet has a CRC
or bit-stuff error.
2
OVER
R/W
0x0
Overrun.
Software must clear this bit.
This bit is only valid when the endpoint is operating in Isochronous
mode. In Bulk mode, it always returns zero.
0x0 = No overrun error.
0x1 = Indicates that an OUT packet cannot be loaded into the
receive FIFO.
1
FULL
R
0x0
FIFO Full.
0x0 = The receive FIFO is not full.
0x1 = No more packets can be loaded into the receive FIFO.
0
RXRDY
R/W
0x0
Receive Packet Ready.
If the AUTOCLR bit in the USBRXCSRHn register is set, then the
this bit is automatically cleared when a packet of USBRXMAXPn
bytes has been unloaded from the receive FIFO.
If the AUTOCLR bit is clear, or if packets of less than the maximum
packet size are unloaded, then software must clear this bit manually
when the packet has been unloaded from the receive FIFO.
0x0 = No data packet has been received.
0x1 = A data packet has been received. The EPn bit in the
USBRXIS register is also set in this situation.