
PRELIMINARY
XRT86SH221
16
REV. P1.0.5
SDH-TO-PDH FRAMER/MAPPER WITH INTEGRATED 21-CHANNEL E1 SH LIU
J3
J4
TxOHFRAME
I/O
Transmit SOH/POH Overhead Frame Boundary Indicator
The Transmit SOH/POH Data Input Port will pulse this output pin
"High" for one period of TxOHCLK, coincident to whenever it is
processing the very first SOH byte of a given outbound STM-0/
STM-1 frame in the Section Overhead (A1) and the very first bit
of the Path Overhead (J1). If TxPOH_IND is "Low" during this
Frame Pulse, then that bit is A1. If TxPOH_IND is "High" during
this Frame Pulse, then that bit is J1. This pin will be pulled "Low"
at all other times.
H1
F1
TxOHINS
I
Transmit SOH/POH Overhead Insertion Input
If the System Side Terminal Equipment intends to insert its own
value for a given overhead SOH or POH byte into the outbound
STM-0 or STM-1 data-stream, then this input pin should be
pulled "High" coincident with the SOH or POH bytes. This input
pin is sampled upon the rising edge of TxOHCLK.
F1
K5
TxPOH_IND
I/O
Transmit POH Indicator
The Transmit SOH/POH Data Input Port will toggle and hold this
output pin "High", coincident to whenever it is ready to accept
POH data via the TxOH input pin. Conversely, this pin will hold
this pin "Low", coincident to whenever it is ready to accept SOH
data via the TxOH input pin. This pin will be updated on the fall-
ing edge of TxOHCLK as an output (or sampled on the rising
edge as an input).
1.9
HIGH SPEED TU POH OVERHEAD BUS
388 B
ALL
568 B
ALL
P
IN
N
AME
T
YPE
D
ESCRIPTION
Receive TU POH Extraction Bus
W4
AA5
RxTUPOH
O
Receive TU POH Data Output Port
This output pin will output the contents of the VC-4 POH bytes
within the incoming STM-1 data-stream. This output is updated
on the falling edge of RxTUPOHCLK.
AA2
AB4
RxTUPOHCLK
O
Receive TU POH Overhead Clock Output
If the XRT86SH221 along with two other devices has been con-
figured to operate in the STM-1/TUG-3 Mode, this output clock
signal is used as the timing reference for the Receive VC-4 POH
Overhead Extraction Bus. This clock will update all output extrac-
tion bus pins on its falling edge.
AD1
AD2
RxTUPO-
HFRAME
O
Receive TU POH Data Output Port - Frame Boundary Output
The Receive TU POH Data Output Port will pulse this output pin
"High" for one period of RxTUPOHCLK, coincident to whenever
it is extracting the very first bit of the VC-4 POH. This pin will be
pulled "Low" at all other times.
AA3
AB5
RxTUPOHVALID
O
Receive TU POH Data Output Port - Overhead Indicator Out-
put
This output pin will be pulled "High" when the extracted VC-4
POH bytes are ready to be sampled from the overhead bus. This
pin will be pulled "Low" at all other times.
1.8
HIGH SPEED SECTION AND PATH OVERHEAD BUS
388 B
ALL
568 B
ALL
P
IN
N
AME
T
YPE
D
ESCRIPTION