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Intel
®
IXP45X and Intel
®
IXP46X Product Line of Network Processors—USB 1.1 Device
Controller
Intel
®
IXP45X and Intel
®
IXP46X Product Line of Network Processors
Developer’s Manual
August 2006
316
Order Number: 306262-004US
8.5.12.5
Sent STALL (SST)
The sent stall bit is set by the UDC in response to FST successfully forcing a user-
induced STALL on the USB bus. This bit is not set if the UDC detects a protocol violation
from the host PC when a STALL handshake is returned automatically. In either event,
the Intel XScale processor does not intervene and the UDC clears the STALL status
when the host sends a CLEAR_FEATURE command.
The endpoint operation continues normally and does not send another STALL condition,
even if the UDCCS10[SST] bit is set.
To allow the software to continue to send the STALL condition on the USB bus, the
UDCCS10[FST] bit must be set again. The Intel XScale processor writes a 1 to the sent
stall bit to clear it.
8.5.12.6
Force STALL (FST)
The Intel XScale processor can set the force stall bit to force the UDC to issue a STALL
handshake to all IN tokens. STALL handshakes continue to be sent until the Intel
XScale processor clears this bit by sending a Clear Feature command.
The UDCCS10[SST] bit is set when the STALL state is actually entered, but this may be
delayed if the UDC is active when the UDCCS10[FST] bit is set. The UDCCS10[FST] bit
is automatically cleared when the UDCCS10[SST] bit is set.
To ensure that no data is transmitted after the Clear Feature command is sent and the
host resumes IN requests, software must clear the transmit FIFO by setting the
UDCCS10[FTF] bit.
8.5.12.7
Bit 6 Reserved
Bit 6 is reserved for future use.
8.5.12.8
Transmit Short Packet (TSP)
Software uses the transmit short packet to indicate that the last byte of a data transfer
has been sent to the FIFO. This indicates to the UDC that a short packet or zero-sized
packet is ready to transmit. Software should always check TSP after loading a packet to
determine if more data can be loaded.
Software must not set this bit if a packet of 8 bytes is to be transmitted. When the data
packet is successfully transmitted, the UDC clears this bit.
Register Name:
UDCCS10
Hex Offset Address:
0x C800B038
Reset Hex Value:
0x00000001
Register
Description:
Universal Serial Bus Device Controller Endpoint 10Control and Status Register
Access: Read/Write
Bits
31
8
7
6
5
4
3
2
1
0
(Reserved)
TS
P
(Rsvd
)
FST
SS
T
TU
R
FT
F
TPC
TFS
X
0
0
0
0
0
0
0
1
Resets (Above)