PMC-Sierra PM5349 manual Tfpi, Tclk

		PMC-Sierra, Inc.	PM5349 S/UNI-QUAD
S/UNI-QUAD
DATASHEET
PMC-971239	ISSUE 6		SATURN USER NETWORK INTERFACE (155-QUAD)

Pin Name	Type	Pin	Function
		No.
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.

Proprietary and Confidential to PMC-Sierra, Inc., and for its Customers’ Internal Use 14