17.5.40 USB Host Transmit Interval Endpoint n Register (USBTXINTERVAL[1]USBTXINTERVAL[3])
The USB host transmit interval endpoint
n
8-bit registers (USBTXINTERVAL[
n
]), for interrupt transfers, define 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 USBTXINTERVAL[
n
] registers values define a number of frames, as follows:
Table 17-53. USBTXINTERVAL[n] Frame Numbers
Transfer Type
Speed
Valid Values (m)
Interpretation
Interrupt
Low-speed or Full-speed
0x01-0xFF
The polling interval is
m
frames.
Bulk
Full-speed
0x02-0x10
The NAK Limit is 2
(m-1)
frames. A value of 0 or 1 disables
the NAK timeout function.
For the specific offset for each register, see
Mode(s):
Host
The USBTXINTERVAL[
n
] registers are shown in
Figure 17-52. USB Host Transmit Interval Endpoint n Register (USBTXINTERVAL[n])
7
0
TXPOLL / NAKLMT
R/W-0
LEGEND: R/W = Read/Write; -
n
= value after reset
Table 17-54. USB Host Transmit Interval Endpoint n Register(USBTXINTERVAL[n]) Field Descriptions
Bit
Field
Value
Description
7-0
TXPOLL /
NAKLMT
0
TX Polling / NAK Limit The polling interval for interrupt transfers; the NAK limit for bulk transfers. See
for valid entries; other values are reserved.
Universal Serial Bus (USB) Controller
1122
TMS320x2806x Microcontrollers
SPRUH18I – JANUARY 2011 – REVISED JUNE 2022
Copyright © 2022 Texas Instruments Incorporated
Содержание TMS320 2806 Series
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