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Preliminary Data Sheet, Rev. 1
October 2000
TMXF28155 Super Mapper
155/51 Mbits/s SONET/SDH x28/x21 DS1/E1
255
Lucent Technologies Inc.
VT/TU Mapper Functional Description
(continued)
VT Pointer Interpreter (VTPI)
(continued)
I
The pointer interpreter will transition into the DEC state based on the following conditions:
— When operating in the 8 of 10 mode (VT_8ORMAJORITY = 1(Table 181)), if 8 of the 10 I and D bits are correct
for a pointer decrement on the incoming V1 and V2 bytes, the pointer interpreter will transition into the DEC
state. Otherwise, if 3 of the 5 I bits and 3 of the 5 D bits are correct for a pointer decrement on the incoming
V1 and V2 bytes, the pointer interpreter will transition into the DEC state.
I
The pointer interpreter will transition out of the DEC state based on the following conditions:
— If NDF is enabled on the incoming V1 and V2 bytes, the pointer interpreter will transition from the DEC state
into the NDF state.
— Following three consecutive superframes with all 1s in the V1 and V2 bytes, the pointer interpreter will transi-
tion from the DEC state into the AIS-V state.
— Following three new consecutive, consistent, and valid pointers, the pointer interpreter will transition from the
DEC state into the NORM state.
— Following any three consecutive, consistent, and valid pointers, the pointer interpreter will transition from the
DEC state into the NORM state.
— Following the number of consecutive invalid pointers programmed in bits VT_INV_NTIME[3:0] (Table 183), the
pointer interpreter will transition from the DEC state into the LOP-V state.
Pointer increments and decrements are monitored and counted internally. The performance monitoring reset sig-
nal transfers the count to the holding registers for pointer increment (VT_PTR_INC[1—28][3:0] (Table 208)), and
pointer decrement (VT_PTR_DEC[1—28][3:0] (Table 208)) for microprocessor read and resets the running count
registers to 0. When SMPR_SAT_ROLLOVER = 1 (Table 15), the internal running counts will hold at their maxi-
mum value. Otherwise, the counts will roll over. The running count and holding register counts will be forced to 0, if
the SPE mapper is requesting AUTO AIS or VT_LOP[1—28] = 1 (loss of pointer) (Table 177) or VT_AIS[1—28] =
1 (VT AIS) (Table 177) (or VT_H4LOMF = 1 (loss of H4 multiframe alignment) (Table 176)).
LOP-V (VT_LOP) and AIS-V (VT_AIS) will be detected and reported to the microprocessor. Both the LOP-V and
AIS-V conditions will contribute to the VT/TU mapper automatic AIS generation that is driven over a 28-bit internal
output bus to the cross connect (XC). Any change in state of VT_LOP or VT_AIS will be reported to the micropro-
cessor via VT_LOP_D[1—28] and VT_AIS_D[1—28] (Table 169). Unless the appropriate mask bit is set
(VT_LOP_M[1—28] or VT_AIS_M[1—28]) (Table 173), VT_LOP_D[1—28] = 1 or VT_AIS_D[1—28] = 1 will gener-
ate an interrupt.
A check for VT/TU size mismatches is performed by comparing the expected VT/TU size bits (VT1.5 = 11, VT2 =
10) with the actual received SS bits in the V1 byte. After three consecutive mismatches, size errors will be reported
with bit VT_SIZERR[1—28] (Table 177). Any change in state of VT_SIZERR[1—28] will be reported with bit
VT_SIZERR_D[1—28] (Table 169). Unless the VT_SIZERR_M[1—28] (Table 173) mask bit is set,
VT_SIZERR_D[1—28] = 1 will generate an interrupt.
The accepted pointer is stored and accessible by the microprocessor.
This block supports tributary loopback.