
Preliminary Data Sheet, Rev. 1
October 2000
TMXF28155 Super Mapper
155/51 Mbits/s SONET/SDH x28/x21 DS1/E1
99
Lucent Technologies Inc.
TMUX Functional Description
(continued)
Receive Direction (Receive Path from Sonet/SDH)
(continued)
Descrambler
A frame synchronous descrambler of length 127 and generating polynomial x
7
+ x
6
+ 1 will descramble the entire
STS-3/STM-1 (or STS-1) signal except for the first row of overhead. The scrambler will be set to 1111111 on the
first byte following the last section overhead byte in the first row (i.e., after byte J0 for STS-1). The descrambler
operates in a byte wide mode.
The frame descrambler can be enabled or disabled using register bit TMUX_RHSDSCR (Table 55).
F1 Monitor
The TMUX monitors the fault location byte TMUX_RF1MON0[7:0] (Table 63). A new fault location state will be
detected after the number of
consecutive consistent occurrences of a new pattern in the F1 overhead byte as
determined by the value programmed in TMUX_CNTDF1[3:0] (Table 60).
The TMUX maintains a history of
the previous, valid
F1 byte in TMUX_RF1MON1[7:0] (Table 63), and any changes will be reported via TMUX_RF1MOND—delta state
(Table 44) and TMUX_RF1MONM—interrupt mask (Table 48).
This continuous N times detection counter will be reset to 0 upon the transition of the framer into the out of frame
state.
B2 BIP-8 Check
A B2 BIP-8 even parity is computed over all the incoming bits (except for the nine section overhead bytes) of the
STS-1 frame after descrambling, and compared to the B2 byte received in the next frame. The total number of B2
BIP-8 bit errors (raw count), or block errors (as determined by TMUX_BITBLKB2 (Table 56)) is counted. Upon the
assertion of the performance monitor control signal as configured in the microprocessor interface, the raw count
will be reset to zero and the value transferred to an 18-bit holding register for B2 error counts
(TMUX_B2ECNT[17:0] (Table 87)). In case of overflow, depending on the value programmed in the microproces-
sor interface register bit SMPR_SAT_ROLLOVER (Table 15), the B1 error counter will either roll over or saturate at
the maximum value until cleared.
Automatic Protection Switch (APS) Monitor
The TMUX monitors the receive APS value (the K1 byte, and the five most significant bits of the K2 byte) and
stores this value in TMUX_RAPSMON[12:0] (Table 64). This register is updated after the reception of a pro-
grammed number of identical consecutive frames as determined by the value in TMUX_CNTDK1K2[3:0]
(Table 60). Whenever the contents of TMUX_RAPSMON[12:0] changes, a delta bit, TMUX_RAPSMOND will be
set (Table 44) and the interrupt can be masked using TMUX_RAPSMONM (Table 48). This indication also contrib-
utes to a separate device interrupt indication specifically intended for automatic protection switching.
The TMUX monitors this same 13-bit APS value (K1[7:0], K2[7:3]) in the receive direction and reports when the
APS value is inconsistent, using TMUX_RAPSBABE—event (Table 44) and TMUX_RAPSBABM—interrupt mask
(Table 48). Inconsistent APS bytes are defined as the number of successive frames of ASP data where no frames
satisfy the criteria for updating the TMUX_RAPSMON register. The number of inconsistent frames allowed before
reporting is programmed in TMUX_CNTDK1K2FRAME[3:0] (default = 12, see Table 60). This continuous N times
detection counter will be reset to 0 upon the transition of the framer into the out-of-frame state or upon the detec-
tion of a B1 error.