Register Descriptions
1343
SPRUH22I – April 2012 – Revised November 2019
Copyright © 2012–2019, Texas Instruments Incorporated
M3 Universal Serial Bus (USB) Controller
Table 18-46. USB Transmit Control and Status Endpoint n High Register (USBTXCSRH[n])
in OTG A/Host Mode Field Descriptions (continued)
Bit
Field
Value
Description
0
DT
Data Toggle. When read, this bit indicates the current state of the transmit endpoint data toggle.
If DTWE is High, this bit can be written with the required setting of the data toggle. If DTWE is Low, any
value written to this bit is ignored. Care should be taken when writing to this bit as it should only be
changed to RESET the transmit endpoint.
The USBTXCSRH[
n
] registers in OTG B/Device Mode are shown in
and described in
.
Figure 18-44. USB Transmit Control and Status Endpoint n High Register (USBTXCSRH[n])
in OTG B/Device Mode
7
6
5
4
3
2
1
0
AUTOSET
ISO
MODE
DMAEN
FDT
DMAMOD
Reserved
R/W-0
R/W-0
R/W-0
R/W-0
R/W-0
R/W-0
R-0
LEGEND: R/W = Read/Write; -
n
= value after reset
Table 18-47. USB Transmit Control and Status Endpoint n High Register (USBTXCSRH[n])
in OTG B/Device Mode Field Descriptions
Bit
Field
Value
Description
7
AUTOSET
Auto Set
0
The TXRDY bit must be set manually.
1
Enables the TXRDY bit to be automatically set when data of the maximum packet size (value in
USBTXMAXP[
n
]) is loaded into the transmit FIFO. If a packet of less than the maximum packet size is
loaded, then the TXRDY bit must be set manually.
6
ISO
Isochronous Transfers
0
Enables the transmit endpoint for bulk or interrupt transfers.
1
Enables the transmit endpoint for isochronous transfers.
5
MODE
Mode
Note:
This bit only has an effect when the same endpoint FIFO is used for both transmit and receive
transactions.
0
Enables the endpoint direction as RX.
1
Enables the endpoint direction as TX.
4
DMAEN
DMA Request Enable
Note:
Three TX and three /RX endpoints can be connected to the
μ
DMA module. If this bit is set for a
particular endpoint, the DMAATX, DMABTX, or DMACTX field in the USB DMA Select (USBDMASEL)
register must be programmed correspondingly.
0
Disables the
μ
DMA request for the transmit endpoint.
1
Enables the
μ
DMA request for the transmit endpoint.
3
FDT
Force Data Toggle
0
No effect
1
Forces the endpoint DT bit to switch and the data packet to be cleared from the FIFO, regardless of
whether an ACK was received. This bit can be used by interrupt transmit endpoints that are used to
communicate rate feedback for isochronous endpoints.
2
DMAMOD
DMA Request Mode
Note:
This bit must not be cleared either before or in the same cycle as the above DMAEN bit is
cleared.
0
An interrupt is generated after every
μ
DMA packet transfer.
1
An interrupt is generated only after the entire
μ
DMA transfer is complete.
0
Reserved
0
Reserved