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S/UNI-QUAD
PMC-Sierra, Inc.
PM5349 S/UNI-QUAD
DATASHEET
PMC-971239 ISSUE 6 SATURN USER NETWORK INTERFACE (155-QUAD)
Proprietary and Confidential to PMC-Sierra, Inc., and for its Customers’ Internal Use
14
Pin Name Type Pin
No.
Function
TFPI Input Y7 The active high framing position (TFPI) signal is an
8 kHz timing marker for the transmitter. TFPI is used
to align the SONET/SDH transport frame generated
by the S/UNI-QUAD device to a system reference.
TFPI is internally used to align a master frame pulse
counter. When TFPI is not used, this counter is free-
running.
TFPI should be brought high for a single TCLK
period every 2430 (STS-3c (STM-1)) TCLK cycles,
or a multiple thereof. TFPI shall be tied low if such
synchronization is not required. TFPI cannot be
used as an input to a loop-timed channel. For TFPI
to operate correctly it is required that the
TCLK/TFPO output be configured to output the
CSU byte clock.
The TFPI_EN register bits allow to individually
configure each channel to use the global framing
pulse counter and TFPI for framing alignment.
TFPI is sampled on the rising edge of TCLK, but
only when the TTSEL register bit is set to logic zero.
When TTSEL is set to logic one, TFPI is unused.
This pin is shared by all channels.
TCLK Output AC11 The transmit byte clock (TCLK) output provides a
timing reference for the S/UNI-QUAD self-timed
channels. TCLK always provide a divide by eight of
the synthesized line rate clock and thus has a
nominal frequency of 19.44 MHz. TFPI is sampled
on the rising edge of TCLK. TCLK does not apply to
internally loop-timed channels, in which case the
channel’s RCLK provides transmit timing
information.