Registers
1720
SPRUH82C – April 2013 – Revised September 2016
Copyright © 2013–2016, Texas Instruments Incorporated
Universal Serial Bus 2.0 (USB) Controller
34.4.35 Control Status Register for Peripheral Transmit Endpoint (PERI_TXCSR)
The control status register for peripheral transmit endpoint (PERI_TXCSR) is shown in
and
described in
Figure 34-61. Control Status Register for Peripheral Transmit Endpoint (PERI_TXCSR)
15
14
13
12
11
10
9
7
AUTOSET
ISO
MODE
DMAEN
FRCDATATOG
DMAMODE
Reserved
R/W-0
R/W-0
R/W-0
R/W-0
R/W-0
R/W-0
R-0
6
5
4
3
2
1
0
CLRDATATOG
SENTSTALL
SENDSTALL
FLUSHFIFO
UNDERRUN
FIFONOTEMPTY
TXPKTRDY
W-0
R/W-0
R/W-0
W-0
R/W-0
R/W-0
R/W-0
LEGEND: R/W = Read/Write; R = Read only; W = Write only; -
n
= value after reset
Table 34-65. Control Status Register for Peripheral Transmit Endpoint (PERI_TXCSR)
Field Descriptions
Bit
Field
Value
Description
15
AUTOSET
0
DMA Mode: The CPU needs to set the AUTOSET bit prior to enabling the Tx DMA.
1
CPU Mode: If the CPU sets the AUTOSET bit, the TXPKTRDY bit will be automatically set when
data of the maximum packet size (value in TXMAXP) is loaded into the Tx FIFO. If a packet of less
than the maximum packet size is loaded, then the TXPKTRDY bit will have to be set manually.
14
ISO
0-1
Set this bit to enable the Tx endpoint for Isochronous transfers, and clear it to enable the Tx
endpoint for Bulk or Interrupt transfers.
13
MODE
0-1
Set this bit to enable the endpoint direction as Tx, and clear the bit to enable it as Rx.
Note: This bit has any effect only where the same endpoint FIFO is used for both Transmit and
Receive transactions.
12
DMAEN
0-1
Set this bit to enable the DMA request for the Tx endpoint.
11
FRCDATATOG
0-1
Set this bit to force the endpoint data toggle to switch and the data packet to be cleared from the
FIFO, regardless of whether an ACK was received. This can be used by Interrupt Tx endpoints
that are used to communicate rate feedback for Isochronous endpoints.
10
DMAMODE
0-1
This bit should always be set to 1 when the DMA is enabled.
9-7
Reserved
0
Reserved
6
CLRDATATOG
0-1
Write a 1 to this bit to reset the endpoint data toggle to 0.
5
SENTSTALL
0-1
This bit is set automatically when a STALL handshake is transmitted. The FIFO is flushed and the
TXPKTRDY bit is cleared. You should clear this bit.
4
SENDSTALL
0-1
Write a 1 to this bit to issue a STALL handshake to an IN token. Clear this bit to terminate the stall
condition.
Note: This bit has no effect where the endpoint is being used for Isochronous transfers.
3
FLUSHFIFO
0-1
Write a 1 to this bit to flush the next packet to be transmitted from the endpoint Tx FIFO. The FIFO
pointer is reset and the TXPKTRDY bit is cleared.
Note: FlushFIFO has no effect unless the TXPKTRDY bit is set. Also note that, if the FIFO is
double-buffered, FlushFIFO may need to be set twice to completely clear the FIFO.
2
UNDERRUN
0-1
This bit is set automatically if an IN token is received when TXPKTRDY is not set. You should
clear this bit.
1
FIFONOTEMPTY
0-1
This bit is set when there is at least 1 packet in the Tx FIFO. You should clear this bit.
0
TXPKTRDY
0-1
Set this bit after loading a data packet into the FIFO. It is cleared automatically when a data packet
has been transmitted. An interrupt is generated (if enabled) when the bit is cleared.