
Preliminary Data Sheet, Rev. 1
October 2000
TMXF28155 Super Mapper
155/51 Mbits/s SONET/SDH x28/x21 DS1/E1
97
Lucent Technologies Inc.
TMUX Functional Description
(continued)
Receive Direction (Receive Path from Sonet/SDH)
(continued)
Input Clock and Loss-of-Signal Monitoring
The TMUX detects and reports the loss of the 155 MHz input clock for STS-3 mode and the loss of the
51.84 MHz clock for STS-1 mode with register bits TMUX_RHSILOC—state (Table 53), TMUX_RHSILOCD—delta
state (Table 44), TMUX_RHSILOCM—interrupt mask (Table 48). LOC is determined by a stuck high or stuck low
for a time greater than 10 μs and uses the microprocessor clock as its reference.
The TMUX will detect and report a loss-of-signal condition with register bits TMUX_RHSLOS—state (Table 53),
TMUX_RHSLOSD—delta state (Table 44), TMUX_RHSLOSM—interrupt mask (Table 48), by monitoring the exter-
nal input signal pin, LOSEXT (pin AE5) or detecting a continuous all-zeros/ones pattern for 51.44 ns to 105 μs in
51.44 ns steps, before data is descrambled. The detection time is determined by the value programmed in register
bits, TMUX_LOSDETCNT[10:0] (Table 59). The LOS state will clear after reception of two consecutive receive
frames with the correct framing pattern spaced 125 μs apart without an incoming LOS all zeros/ones pattern. This
recovery applies to both internal and external LOS failure causes.
High-Speed Loopback Select Logic
The device can be configured to loopback the transmit STS-3/STM-1 (AU-4) TMUX_THS2RHSLB = 1 (Table 55)
or accept the local STS-3/STM-1 (AU-4) signal TMUX_THS2RHSLB = 0.
Frame Alignment—STS-3/STM-1 (AU-4) Framing or STS-1 Framing
The device will frame on the incoming signal. The state of the framer, out of frame (OOF) (register bit
TMUX_RHSOOF, see Table 53) as well as any changes to this state (register bits TMUX_RHSOOFD—delta state,
see Table 44 and TMUX_RHSOOFM—interrupt mask, see Table 48) will be reported.
The 32-bit (A1-2, A1-3, A2-1, and A2-2) framing pattern will be used in the frame detection for the
STS-3/STM-1 case and a 16-bit pattern will be used for the STS-1 case. The device will be considered out of frame
until two successive framing patterns separated in time by 125 μs occur without framing byte errors.
The device will be considered in frame until five
successive frames separated in time by 125 μs occur with errored
framing patterns. If the framer transitions to the out of frame state, the framer will remain synchronized to the last
known frame boundary or the latest detected unerrored framing pattern.
A loss of frame (LOF) (register bit TMUX_RHSLOF, see Table 53) state bit as well as any changes to this state
(register bits TMUX_RHSLOFD—delta state, see Table 44, TMUX_RHSLOFM—interrupt mask, see Table 48) will
be reported. These state and mask and delta bits are the same for both types of input data, STS-3/STM-1 or STS-
1.
The device will be considered in the LOF state when an OOF condition persists for 24
consecutive frames (3 ms).
The device will transition out of the LOF state after receiving 24 consecutive frames with the correct framing pat-
terns spaced 125 μs apart and the OOF condition is clear.