MT8926
CSTo
3
4-6
PCSW PS PCSW
W
1-3
4-6
0-2
7
PM
SW
8-10
11
12-14
PCSW CRC PCSW
15
MS
W1
16-18
PCSW
19 20-22 23 24-26 27
28-30 31
EF PCSW BPV PCSW Rx PCSW MS
EC
2
BOM
W2
16-18
19-21
22-24
T1
7-9
10-12
13-15
PMAC Miscellaneous
Status Word
Bit
7-5
4
3
2
1
0
Function
Not Used
LLDD (001)
LLED (00001)
FECV
TMR (2SEC)
BOMV
Cyclic Redundancy
Check-6 Error Counter
Bit
7
0
Function
MSB
LSB
Master Status Word 1
Bit
7*
6*
5
4
3*
2
1*
0*
Function
YLALR
MIMIC
ALRM
RAI (ESF YELLOW)
MFSYNC
LOS
SLIP
SYN
Bit
7-4
3-0
Errored Frame
Event Counter
Function
SE (MSB-LSB)
FE (MSB-LSB)
Received Bit-Oriented
Message Register
Bit
7
0
Function
Received First
Received Last
Master Status Word 2
Bit
7*
6*
5*
4
3
2
1
0
Function
BlAlm
FrCnt
Xst
SEI
FSI
CSI
BSI
AIS
Bipolar Violation Counter
Bit
7
0
Function
MSB
LSB
PCSW = Per Channel Status Word
PSW = Phase Status Word
* MT8976/77 Data unaltered by
the MT8926
Figure 5 - CSTo Channel Allocation Versus T1 Channels
connects to DSTi1 of the PMAC and to the receive
side of the system. This allows the PMAC to perform
a payload loopback by internally connecting DSTi1 to
DSTo. In normal operation, transmit data will flow
from DSTi0 to DSTo of the PMAC to DSTi of the
MT8976/77.
PMAC RESET
The MT8926 functions may be suspended by making
the RESET input low (RESET must be high for
normal operation). In the reset state, data entering
the PMAC on FDLi, DSTi0 and CSTi0 will pass
through unaltered to FDLo, DSTo and CSTo
respectively. E8Ko will be high, IRQ will be high
impedance and the 1SEC output (and TMR bit) will
be low.
After the MT8976/77 has acquired frame synchroni-
zation and RESET returns high, the MT8926 will
require two superframes to acquire synchronization
and two ST-BUS frames to align to the ST-BUS.
RESET can be used to prevent DS1 interface
RxA
RxB
ECLK
To PMAC
Control
4 to 1 MUX
CSTi1
Repeating
00001
DSTo
ST-BUS Transmit
Data Stream
ST-BUS Receive
Data Stream
DSTi0
DSTi1
DSTi
TxA
CSTi1
From System
Control
MT8976/77
MT8926
Repeating
001
DSTo
TxB
LCW
LCW
00
01
10
11
Function
DSTi0 to DSTo
DSTi1 to DSTo
00001 to DSTo (activate)
001 to DSTo (deactivate)
LCW = Loopback Control Word
Figure 6 - Payload and Line Loopback Operation
4-8
MITEL [ MITEL NETWORKS CORPORATION ]
