cx29600 Mindspeed Technologies, cx29600 Datasheet - Page 71

• Manufacturer Part Number: cx29600
• Description: Optiphytm - M155 Sts-3 Sonet/sdh Multiplexer
• Manufacturer: Mindspeed Technologies

CX29600
CX29600 Data Sheet
2.4.3 Line Overhead
Table 2-15. Line Overhead Transmit and Receive Functions
29600-DSH-001-B
2.4.3.1 H1 and H2
2.4.3.2 H3
The Line Overhead handles the transport of path-level payloads across the
physical medium. This layer of the overhead provides synchronization and
multiplexing functions, including maintenance and line protection, for the Line
layer. The Section Overhead must be terminated before the Line Overhead can be
accessed. The transmit and receive functions of the Line Overhead are shown in
Table
NOTE:
Two bytes—H1 and H2—in the STS-3/STM-1 frame are fixed on the transmit
side to locate path overhead byte J1 immediately after the Z0 byte of the Section
Overhead. H1 and H2 carry a fixed pointer value of 620Ah as the default. Bits 5
and 6 of the H1 byte contain the values from TXPNTR (for the respective STS-1)
bits 7 and 6. This allows the SS bits to be set to any value to accommodate SDH
pointers. If TXPNTR bit 5 is high, the H1/H2 bytes will each contain 33h as an
invalid pointer value.
the STS-3 SPE. Increment, decrement, and New Data Flag capability is included.
The current pointer position and status is reported in the RXPNTR and
PNTRSTAT registers. Positive and negative pointer justifications are counted in
PJCNT and NJCNT, respectively. New Data Flags are counted in NDFCNT. The
H1 and H2 bytes from the first STS-1 position can be replicated into the second
and third STS-1 positions when the data is transferred downstream.
AIS-L, AIS-P, or LOP-P conditions.
On the receive side, this byte is used during negative justification. Otherwise it is
unused.
H1/H2
H3
B2
K1/K2
D4-12
S1
Z1
Z2
M1
E2
For the H1 and H2, a full pointer processor is implemented for STS-3 to locate
Pointer justification and New Data Flag counts are disabled during LOS, LOF,
On the transmit side, it is always set to 00.
Byte
2-15.
Undefined overhead positions carry 00h.
Mindspeed Technologies
620A/93FF hex pointer
00 hex
Calculated, error insertion
Insertable via register
00 hex or external serial access
Insertable via register
From the TXZ1b/TXZ1c registers
From the TXZ2a/TXZ2b registers
Line FEBE inserted
From the TxE2 pin
Transmit
2.4 SONET/SDH Framer and Overhead Processor
™
Full GR.253 pointer processor
Used for negative justification
Checked, errors counted
Checked, interrupt on change
External serial access
Checked, interrupt on change
To the RXZ1b/RXZ1c registers
To the RXZ2a/RXZ2b registers
Checked, errors counted
To the RxE2 pin
2.0 Functional Description
Receive
2-27