
TMXF28155 Super Mapper
155/51 Mbits/s SONET/SDH x28/x21 DS1/E1
Preliminary Data Sheet, Rev. 1
October 2000
438
Lucent Technologies Inc.
28-Channel Framer Block Functional Description
(continued)
Facility Data Link
(continued)
The Sa bits are stored in the Tx stack as follows.
Table 320. Shared Tx Stack Format for CEPT Frame
Transmission of the Sa stack will take 4 ms, during which time the host should refill the system stack if the Sa bits
need to change.
Near the beginning of each CEPT double multiframe, the Tx data link block will determine whether a new set of Sa
bits is available to be transmitted. The host will indicate this state by resetting the Tx stack empty bit. If this is the
case, the new Sa bits will be transmitted, otherwise, the previous Sa bits will be retransmitted. If the Tx stack empty
bit was 0 at the beginning of the CEPT double multiframe, then the bit will be set to 1 indicating a request for new
Sa bits.
When enabled using the FRM_ASRC (Table 447) bit, the SA bits should only be inserted when the proper align-
ment has been reached. For CEPT links only BFA is required for insertion. For CEPT CRC-4 links both BFA and
MFA need to be valid. This effects the insertion of Sa bits and the reporting of stack empty to the host. There is
another configuration bit FRM_TXCRCSM (Table 447) which allows the CEPT CRC-4 links to insert when only BFA
is active (FRM_TXCRCSM).
Before enabling a link for CEPT format, the host should initialize the stack and set the Tx stack empty bit to 0. If
not, the data link block will transmit the reset state of the stack which is arbitrary.
Transmit Data Link Stack Idle Modes
n
D4
n
J-D4
n
J2
n
CMI
n
No Data Link Features
SLC-96, DDS, or CEPT ESF Frame Alignment
For CEPT, DDS, or SLC-96 frames, loss of frame alignment is not an issue since the framer is the source of time
slot 0 or the F bits. Once a link is enabled, the frame sequence always starts at the beginning.
In the case of the system being the source of multiframe alignment, the data link block will simply deliver what is
requested.
Word
0
1
2
3
4
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
SA41 SA43 SA45 SA47 SA49 SA411 SA413 SA415 SA41 SA43 SA45 SA47 SA49 SA411 SA413 SA415
SA51 SA53 SA55 SA57 SA59 SA511 SA513 SA515 SA51 SA53 SA55 SA57 SA59 SA511 SA513 SA515
SA61 SA63 SA65 SA67 SA69 SA611 SA613 SA615 SA61 SA63 SA65 SA67 SA69 SA611 SA613 SA615
SA71 SA73 SA75 SA77 SA79 SA711 SA713 SA715 SA71 SA73 SA75 SA77 SA79 SA711 SA713 SA715
SA81 SA83 SA85 SA87 SA89 SA811 SA813 SA815 SA81 SA83 SA85 SA87 SA89 SA811 SA813 SA815