TM4C1236H6PM Datasheet, PDF (1120/1236 Pages) Texas Instruments – Tiva Microcontroller

Universal Serial Bus (USB) Controller
OTG A /
Host
Register 135: USB Host Transmit Interval Endpoint 1 (USBTXINTERVAL1),
offset 0x11B
Register 136: USB Host Transmit Interval Endpoint 2 (USBTXINTERVAL2),
offset 0x12B
Register 137: USB Host Transmit Interval Endpoint 3 (USBTXINTERVAL3),
offset 0x13B
Register 138: USB Host Transmit Interval Endpoint 4 (USBTXINTERVAL4),
offset 0x14B
Register 139: USB Host Transmit Interval Endpoint 5 (USBTXINTERVAL5),
offset 0x15B
Register 140: USB Host Transmit Interval Endpoint 6 (USBTXINTERVAL6),
offset 0x16B
Register 141: USB Host Transmit Interval Endpoint 7 (USBTXINTERVAL7),
offset 0x17B
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 defines
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
Interrupt
Isochronous
Bulk
Speed
Low-Speed or Full-Speed
Full-Speed
Full-Speed
Valid values (m)
0x01 – 0xFF
0x01 – 0x10
0x02 – 0x10
Interpretation
The polling interval is m frames.
The polling interval is 2^(m-1) frames/micorframes..
The NAK Limit is 2^(m-1) frames/microframes. A
value of 0 or 1 disables the NAK timeout
function.
USB Host Transmit Interval Endpoint n (USBTXINTERVALn)
Base 0x4005.0000
Offset 0x11B
Type RW, reset 0x00
7
6
5
4
3
2
1
0
TXPOLL / NAKLMT
Type RW
RW
RW
RW
RW
RW
RW
RW
Reset
0
0
0
0
0
0
0
0
Bit/Field
7:0
Name
TXPOLL / NAKLMT
Type
RW
Reset
0x00
Description
TX Polling / NAK Limit
The polling interval for interrupt/isochronous transfers; the NAK limit for
bulk transfers. See table above for valid entries; other values are
reserved.
1120
Texas Instruments-Production Data
June 12, 2014