Intel IXP45X Developer's Manual page 308

8.5.8.6 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 UDCCS6[SST] bit is set when the STALL state is actually entered, but this may be
delayed if the UDC is active when the UDCCS6[FST] bit is set. The UDCCS6[FST] bit is
automatically cleared when the UDCCS6[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
UDCCS6[FTF] bit.
8.5.8.7 Bit 6 Reserved
Bit 6 is reserved for future use.
8.5.8.8 Transmit Short Packet (TSP)
The software uses the transmit short packet bit to indicate that the last byte of a data
transfer to the FIFO has occurred. 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 64-byte packet is to be transmitted. When the data
packet is successful transmitted, the UDC clears this bit.
Register Name:
0 x C800B028
Hex Offset Address:
Register
Universal Serial Bus Device Controller Endpoint 6Control and Status Register
Description:
Access: Read/Write
31
Bits
31:8
7
6
5
4
® ®
Intel IXP45X and Intel IXP46X Product Line of Network Processors
Developer's Manual
308
® ®
Intel IXP45X and Intel
(Reserved)
X
Resets (Above)
Register
Name
(Reserved)
Transmit short packet (read/write 1 to set).
TSP
1 = Short packet ready for transmission.
(Reserved). Always reads 0.
Force STALL (read/write).
FST
1 = Issue STALL handshakes to IN tokens.
Sent STALL (read/write 1 to clear).
SST
1 = STALL handshake was sent.
IXP46X Product Line of Network Processors—USB 1.1 Device
UDCCS6
0 x 00000001
Reset Hex Value:
Bits
UDCCS6
(Sheet 1 of 2)
Description
Controller
8 7 6 5 4 3 2 1
0 0 0 0 0 0 0
August 2006
Order Number: 306262-004US
0
1