Intel® IXP42X product line and IXC1100 control plane processors—Universal Serial Bus (USB)
v1.1 Device Controller
Intel® IXP42X Product Line of Network Processors and IXC1100 Control Plane Processor
DM September 2006
530 Order Number: 252480-006US
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.
18.5.33 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 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 87 0
(Reserved) (8-Bit Data)
X 00000000
Resets (Above)
Register UDDR2
Bits Name Description
31:8 Reserved for future use.
7:0 DATA Top of endpoint data currently being read.
Register Name: UDDR3
Hex Offset Address: 0 x C800B200 Reset Hex Value: 0x00000000
Register
Description: Universal Serial Bus Device Endpoint 3 Data Register
Access: Write
Bits
31 16 15 8 7 0
(Reserved) (8-Bit Data)
X 00000000
Resets (Above)
Register UDDR3
Bits Name Description
31:8 Reserved for future use.
7:0 DATA Top of endpoint data currently being loaded.