PM5381-BI PMC-Sierra, Inc., PM5381-BI Datasheet - Page 58

• Manufacturer Part Number: PM5381-BI
• Description: ATM UNI, Single Channel ATM PHY Interface for 2488.32Mbps
• Manufacturer: PMC-Sierra, Inc.

9.5
Proprietary and Confidential to PMC-Sierra, Inc., and for its Customers’ Internal Use
Document ID: PMC-2000489, Issue 4
System Side UTOPIA and POS-PHY Signals (84)
Pin Name
TPOHRDY
TPOHEN
Pin Name
POSL3_UL3B
RFCLK
Type
Output
Input
Type
Input
Input
Pin
No.
AJ25
AK26
Pin
No.
E28
Function
The transmit path overhead insert ready (TPOHRDY)
signal indicates if the S/UNI-2488 is ready to accept the byte
currently on TPOH.
TPOHRDY is set high during the most significant bit of a POH
byte to indicate readiness to accept the byte on the TPOH
input. This byte will be accepted if TPOHEN is also set high.
If TPOHEN is set low, the byte is invalid and is ignored.
TPOHRDY is set low to indicate that the S/UNI-2488 is unable
to accept the byte on TPOH and expects the byte to be re-
presented at the next opportunity.
TPOHRDY is updated on the falling edge of TOHCLK.
The transmit path overhead insert enable (TPOHEN) signal
controls the insertion of the transmit path overhead data
which is inserted in the outgoing stream.
TPOHEN is set high during the most significant bit of a POH
byte to indicate valid data on the TPOH input. This byte will
be accepted for transmission if TPOHRDY is also set high. If
TPOHRDY is set low, the byte is rejected and must be re-
presented at the next opportunity.
Accepted bytes sampled on TPOH are inserted into the
corresponding path overhead byte positions (for the J1, C2,
G1, F2, Z3, Z4, and Z5 bytes) for the master STS-12 slice
only. The byte on TPOH is ignored when TPOHEN is set low
during the most significant bit position.
When the byte at the B3 or H4 byte position on TPOH is
accepted, it is used as an error mask to modify the
corresponding transmit the B3 or H4 path overhead byte,
respectively. The accepted error mask is XORed with the
corresponding B3 or H4 byte before it is transmitted.
TPOHEN should be grounded if it is not used.
TPOHEN is sampled on the rising edge of the TOHCLK.
Function
The UTOPIA/POS-PHY interface select (POSL3_UL3B)
selects between UTOPIA Level 3 and POS-PHY Level 3
modes for the system side interface. When POSL3_UL3B is
low, the UTOPIA Level 3 interface is selected. When
POSL3_UL3B is high, the POS-PHY Level 3 interface is
selected.
The UTOPIA receive FIFO read clock (RFCLK) signal is
used to read ATM cells from the receive cell FIFO.
RFCLK is expected to cycle at 104 MHz.
S/UNI-2488 Telecom Standard Product Datasheet
Released
58