Register Descriptions
1338
SPRUH22I – April 2012 – Revised November 2019
Copyright © 2012–2019, Texas Instruments Incorporated
M3 Universal Serial Bus (USB) Controller
18.5.33 USB NAK Limit Register (USBNAKLMT), offset 0x10B
The USB NAK limit 8-bit read-only register (USBNAKLMT) sets the number of frames after which endpoint
0 should time out on receiving a stream of NAK responses. (Equivalent settings for other endpoints can be
made through their USBTXINTERVAL[
n
] and USBRXINTERVAL[
n
] registers.)
The number of frames selected is 2(m-1) (where m is the value set in the register, with valid values of
2–16). If the Host receives NAK responses from the target for more frames than the number represented
by the limit set in this register, the endpoint is halted.
Note:
A value of 0 or 1 disables the NAK timeout function.
Mode(s):
OTG A or Host
USBNAKLMT is shown in
and described in
Figure 18-40. USB NAK Limit Register (USBNAKLMT)
7
5
4
0
Reserved
NAKLMT
R-0
R/W-0
LEGEND: R/W = Read/Write; -
n
= value after reset
Table 18-43. USB NAK Limit Register (USBNAKLMT) Field Descriptions
Bit
Field
Value
Description
7-5
Reserved
0
Reserved
4-0
NAKLMT
0
EP0 NAK Limit specifies the number of frames after receiving a stream of NAK responses.