
25
x r
PRELIMINARY
E3 UNI FOR ATM
XRT7234
REV. P1.0.0
69
RxData8
O
Receive Utopia Data Bus Output:
This output pin, along with
RxData14 through RxData0 functions as the Receive Utopia Data Bus.
ATM cell data that has been received from the “Far-End” UNI is output on
the Receive Utopia Data Bus, where it can be read and processed by the
ATM Layer Processor.
Note:
This pin is only available for the 160 pin package version.
46
70
RxData0
O
Receive Utopia Data Bus Output—LSB:
This output pin, along with
RxData14 through RxData0 functions as the Receive Utopia Data Bus.
ATM cell data that has been received from the “Far-End” UNI is output on
the Receive Utopia Data Bus, where it can be read and processed by the
ATM Layer Processor.
71
GND
***
Ground Signal Pin
47
72
RxSoC
O
Receive Utopia Interface—Start of Cell Indicator:
This output pin allows
the ATM Layer Processor to determine the boundaries of the ATM cells
that are output via the Receive Utopia Data bus. The Receive Utopia
Interface block will assert this signal when the first byte (or word) of a
new cell is present on the Receive Utopia Data Bus; RxData[15:0].
73
RxAddr4
I
Receive Utopia Address Bus input (MSB):
This input pin, along with
RxAddr3 through RxAddr0 functions as the Receive Utopia Address bus
inputs. These input pins are only active when the UNI device is operating
in the Multi-PHY Mode. The Receive Utopia Address Bus input is sampled
on the rising edge of the RxClk signal. The contents of this address bus
are compared with the value stored in the “Rx UT Address Register
(Address = 7Eh). If these two values match, then the UNI will inform the
ATM Layer Processor on whether or not it has any new ATM cells to be
read from the RxFIFO; by driving the RxClav output to the appropriate
level. If these two address values do not match, then the UNI will not
respond to the ATM Layer Processor; and will keep its RxClav output signal
tri-stated.
48
74
RxPrty
O
Receive Utopia Interface—Parity Output pin:
The Receive Utopia
Interface block will compute the odd-parity of each byte (or word) that it
will place on the Receive Utopia Data Bus. This odd-parity value will be
output on this pin, while the corresponding byte (or word) is present on
the Receive Utopia Data Bus.
75
RxAddr3
I
Receive Utopia Address Bus input:
(See Description for RxAddr4)
PIN DESCRIPTION (CONTINUED)
Pin
No.
100 Pin Package
Pin No. 160
PinPackage
Symbol
Type
Description