![NXP Semiconductors LPC43Sxx Скачать руководство пользователя страница 705](http://html1.mh-extra.com/html/nxp-semiconductors/lpc43sxx/lpc43sxx_user-manual_1721827705.webp)
UM10503
All information provided in this document is subject to legal disclaimers.
© NXP B.V. 2015. All rights reserved.
User manual
Rev. 2.1 — 10 December 2015
705 of 1441
NXP Semiconductors
UM10503
Chapter 25: LPC43xx/LPC43Sxx USB0 Host/Device/OTG controller
25.10.5.2 Stalling
There are two occasions where the device controller may need to return to the host a
STALL:
1. The first occasion is the
functional stall
, which is a condition set by the DCD as
described in the
USB 2.0 device framework (chapter 9)
. A functional stall is only used
on non-control endpoints and can be enabled in the device controller by setting the
endpoint stall bit in the ENDPTCTRLx register associated with the given endpoint and
the given direction. In a functional stall condition, the device controller will continue to
return STALL responses to all transactions occurring on the respective endpoint and
direction until the endpoint stall bit is cleared by the DCD.
2. A
protocol stal
l, unlike a function stall, is only used on control endpoints and is
automatically cleared by the device controller at the start of a new control transaction
(setup phase). When enabling a protocol stall, the DCD should enable the stall bits
(both directions) as a pair. A single write to the ENDPTCTRLx register can ensure that
both stall bits are set at the same instant.
Remark:
Any write to the ENDPTCTRLx register during operational mode must preserve
the endpoint type field (i.e. perform a read-modify-write).
25.10.5.3 Data toggle
Data toggle is a mechanism to maintain data coherency between host and device for any
given data pipe. For more information on data toggle, refer to the
USB 2.0 specification
.
10 - bulk
11 - interrupt
Endpoint Stall
0
Table 510. Device controller endpoint initialization
Field
Value
Table 511. Device controller stall response matrix
USB packet
Endpoint
STALL bit
Effect on
STALL bit
USB response
SETUP packet received by a non-control
endpoint.
N/A
None
STALL
IN/OUT/PING packet received by a
non-control endpoint.
1
None
STALL
IN/OUT/PING packet received by a
non-control endpoint.
0
None
ACK/NAK/NYET
SETUP packet received by a control endpoint. N/A
Cleared
ACK
IN/OUT/PING packet received by a control
endpoint.
1
None
STALL
IN/OUT/PING packet received by a control
endpoint.
0
None
ACK/NAK/NYET