LM3S3748 Datasheet, PDF (574/753 Pages) List of Unclassifed Manufacturers – Microcontroller

Univeral Serial Bus (USB) Controller
Register 74: USB Host Transmit Interval Endpoint 1 (USBTXINTERVAL1),
offset 0x11B
Register 75: USB Host Transmit Interval Endpoint 2 (USBTXINTERVAL2),
offset 0x12B
Register 76: USB Host Transmit Interval Endpoint 3 (USBTXINTERVAL3),
offset 0x13B
Host
USBTXINTERVALn is an 8-bit register that, for interrupt and isochronous transfers, defines the
polling interval for the currently selected transmit endpoint. For bulk endpoints, this register sets the
number of frames after which the endpoint should time out on receiving a stream of NAK responses.
The USBTXINTERVALn register value defines a number of frames, as follows:
Transfer Type
Speed
Valid values (m) Interpretation
Interrupt
Low-Speed or Full-Speed
1 – 255
Polling interval is m frames.
Isochronous
Full-Speed
1 – 16
Polling interval is 2^(m-1) frames.
Bulk
Full-Speed
2 – 16
NAK Limit is 2^(m-1) frames. A value of 0 or 1 disables the NAK
timeout function.
USB Host Transmit Interval Endpoint 1 (USBTXINTERVAL1)
Base 0x4005.0000
Offset 0x11B
Type R/W, reset 0x00
7
6
5
4
3
2
1
0
TXPOLL/NAKLMT
Type R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
Reset
0
0
0
0
0
0
0
0
Bit/Field
7:0
Name
TXPOLL/NAKLMT
Type
R/W
Reset
0x00
Description
TX Polling / NAK Limit
Polling interval for interrupt/isochronous transfers; NAK limit for bulk
transfers.
574
April 08, 2008
Preliminary