tdat04622 ETC-unknow, tdat04622 Datasheet - Page 64

• Manufacturer Part Number: tdat04622
• Description: Tdat Sonet/sdh 155/622/2488 Mbits/s Data Interfaces
• Manufacturer: ETC-unknow

TDAT042G5 SONET/SDH
155/622/2488 Mbits/s Data Interface
Pin Information
Table 5
36
AP21
AK33
AL9
V33
Pin
.
Pin Descriptions—Enhanced UTOPIA Interface Signals (continued)
Symbol
RxPA[D]
RxPA[C]
RxPA[B]
RxPA[A]
(continued)
Type
3.3 V
I/O
O
Receive Cell/Packet Available. This signal indicates when the
TDAT042G5 receive FIFO can send data to the master device.
The RxPA[D:A] signal behavior depends on the provisioned low
watermark in the UTOPIA interface.
I
I
I
I
* ATM Forum Technical Committee, UTOPIA Level 3, STR-PHY-UL3-01.00, July
(See further description on next page.)
1999.
One-Cycle Delay Mode. This mode follows the UTOPIA Level
2 Standard. The RxPA response occurs one cycle after the
address is polled. RxENB is asserted to activate the selected
PHY. RxDATA and RxSOP are output one cycle after RxENB is
sampled active by the PHY device.
Two-Cycle Delay Mode. This mode follows the UTOPIA Level
3 baselined text*. The RxPA response occurs two cycles after
the address is polled. RxENB is asserted to activate the
selected PHY. RxDATA and RxSOP are output two cycles after
RxENB is sampled active by the PHY device.
RxPA[D:A] Assertion. RxPA[D:A] goes high (is asserted)
when the amount of data in the receive FIFO has reached or
exceeded the low watermark or there is end of packet (EOP)
resident in the FIFO.
RxPA[D:A] Deassertion. In ATM mode, the RxPA[D:A] signal
goes low (is deasserted) when the FIFO has less than the low
threshold amount of data and there is no EOP inside the FIFO
(i.e., part of an ATM cell). Once the last byte of the current cell
is transmitted, and if the amount of data within the FIFO is still
less than the low threshold, RxPA[D:A] is deasserted.
In packet mode, the RxPA[D:A] signal goes low (is deasserted)
when the FIFO has less than the low threshold amount of data
and there is no EOP inside the FIFO.
Once the data transfer begins (since the amount of data has
reached or exceeded the low watermark), and if there is no
EOP below the low threshold (i.e., a long packet), the RxPA
signal is deasserted when the FIFO is drained by the UTOPIA
master device. In this case, the master must closely monitor the
RxPA[D:A] signals and use these signals as data valid indica-
tors to ensure that bad data is not read from the TDAT042G5.
TDAT042G5 will deassert the RxPA[D:A] signal immediately
when the FIFO is drained.
Name/Description
Agere Systems Inc.
Data Sheet
May 2001