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Intel
®
IXP45X and Intel
®
IXP46X Product Line of Network Processors
August 2006
Developer’s Manual
Order Number: 306262--, Revision: 004US
343
USB 1.1 Device Controller—Intel
®
IXP45X and Intel
®
IXP46X Product Line of Network
Processors
8.5.32
UDC Data Register 2
(UDDR2)
Endpoint 2 is a double-buffered bulk OUT endpoint that is 64 bytes deep. The UDC will
generate an interrupt as soon as the EOP is received.
Since it is double-buffered, up to two packets of data may be ready. Via direct read
from the Intel XScale processor, the data can be removed from the UDC. If one packet
is being removed and the packet behind it has already been received, the UDC will
issue a NAK to the host the next time it sends an OUT packet to endpoint 2.
This NAK condition will remain in place until a full packet space is available in the UDC
at Endpoint 2.
8.5.33
UDC Data Register 3
(UDDR3)
Endpoint 3 is a double-buffered isochronous IN endpoint that is 256 bytes deep. Data
can be loaded via direct Intel XScale processor writes.
Because it-is double-buffered, up to two packets of data may be loaded for
transmission.
Register
UDDR1
Bits
Name
Description
31:8
Reserved for future use.
7:0
DATA
Top of endpoint data currently being loaded.
Register Name:
UDDR2
Hex Offset Address:
0 x C800B180
Reset Hex Value:
0x00000000
Register
Description:
Universal Serial Bus Device Endpoint 2 Data Register
Access: Read
Bits
31
8
7
0
(Reserved)
(8-Bit Data)
X
0
0
0
0
0
0
0
0
Resets (Above)
Register
UDDR2
Bits
Name
Description
31:8
Reserved for future use.
7:0
DATA
Top of endpoint data currently being read.