DS3181/DS3182/DS3183/DS3184
30
6.5 DS3/E3 Flexible External Fractional (Subrate) Mode Configuration Mode
DS3/E3 Flexible External Fractional Mode allows subrate datastreams to be inserted into a DS3 or E3 line, with the
fractional overhead and payload externally multiplexed. Major functional blocks for the DS3/E3 Flexible External
Fractional Mode are shown in
Figure 6-5. Mapping configuration is programmable on per-port basis and is shown
The “-OHM” modes are not allowed in fractional framing modes since the user cannot distinguish between internal
framing overhead and external framing overhead bit locations.
Table 6-5. DS3/E3 Flexible External Fractional (Subrate) Mode Configuration Registers
MODE
FM[5:0]
SIM[1:0]
PMCPE
PORT.CR2
UTOPIA L2 ATM
0XX110
00
X
UTOPIA L3 ATM
0XX110
01
X
POS-PHY L2 ATM
0XX110
10
1
POS-PHY L3 ATM
0XX110
11
1
POS-PHY L2 Packet
0XX110
10
0
POS-PHY L3 Packet
0XX110
11
0
Figure 6-5. DS3/E3 Flexible External Fractional Mode
TS
OF
On/
T
DE
Nn
RLCLKn
RXPn
RXNn
TPOSn/
TDATn
TNEGn/
TOHMOn
TLCLKn
DS3/E3
Transmit
LIU
IEEE P1149.1
JTAG Test
Access Port
Microprocessor
Interface
HDLC
FEAC
TXPn
TXNn
LLB
DL
B
DS3 / E3
Transmit
Formatter
DS3 / E3
Receive
Framer
Trail
Trace
Buffer
Tx Cell
Processor
Tx
FIFO
System
Interface
Rx Cell
Processor
Rx
FIFO
RO
Hn
RO
HC
LK
n
RO
HS
OF
n
TO
H
n
TO
H
C
LK
n
TO
H
S
OF
n
TC
LK
In
Tx Packet
Processor
RSE
R
n
RS
OF
On
/R
DE
N
n
RC
LK
On
/R
G
C
LK
n
SL
B
Rx Packet
Processor
DS3/E3
Receive
LIU
TAIS
TUA1
T
O
HE
Nn
Clock Rate
Adapter
TX BERT
RX BERT
CL
KA
CL
KB
CL
KC
T
P
DE
NIn
PL
B
AL
B
TSOF
In
UA1
GEN
TC
LK
On/
TG
C
LK
n
TS
E
R
n
TP
D
E
N
O
n
TP
D
A
Tn
RDATn
RPOSn/
RNEGn/
RLCVn/
ROHMIn
RPD
E
NI
n
RST
*
RPD
A
T
n
B3ZS/
HDB3
Encoder
B3ZS/
HDB3
Decoder
n = port # (1-4)