
DS3161/DS3162/DS3163/DS3164
ignored when TOHMOn is high. In the “- OHM Octet” framing modes, the first payload bit after the TOHMOn signal
goes low is the MSB (Bit 1) of a payload Octet.
The TDATn and TOHMOn signals change a small delay after the positive edge of the reference clock signal if the
clock pin is not inverted; other wise they change after the negative edge. The TOHMIn signal is sampled at the
rising edge of the reference clock signal if the clock pin is not inverted; otherwise it is sampled at the negative
edge. The TLCLKn clock pin is the clock reference typically used for the TDATn, TOHMOn and TOHMIn signals,
but they can be time referenced to the TCLKIn, TCLKOn, RLCLKn or RCLKOn clock pins. The TDATn, TOHMOn,
Figure 8-5. TX Line I/O UNI OHM Functional Timing Diagram
TLCLK
TDAT
TOHMI
TOHMO
TDAT GAP FOR EXT OVERHEAD INSERTION
Figure 8-6. TX Line I/O UNI Octet Aligned OHM Functional Timing Diagram
TLCLK
TDAT
TOHMI
TOHMO
ATM Cell /Packet Octet n+1
B1 B2 B3 B4 B5 B6 B7 B8 B1
B6 B7 B8
Octet n
EXT OH BIT LOCATIONS
8.3.1.4
UNI Mode Receive Pin Functional Timing
The RDATn pin is available when the line interface is in the UNI mode. The ROHMIn pin is available when the
framer is in one of the “-OHM” modes. The RLCVn pin is available when the line interface is in the UNI mode and
the framer is not in one of the “-OHM” modes. The line interface is forced into the UNI mode when the framer is in
one of the “-OHM” modes.
The ROHMIn pin is used to mark the RDATn bits that will be ignored by the internal receive logic. When the
ROHMIn pin is high, the internal framers and data sinks will ignore the corresponding RDATn bits. In the “- OHM
Octet” framing modes, the data on RDATn is octet-aligned with the ROHMIn signal, the first bit of the serial data on
RDATn is the MSB (Bit 1) of a payload Octet.
All bits on the RDATn pin, even the bits that are marked by ROHMIn, will come out the RSERn pin, if the RSERn
pin is enabled.
The signal on the RLCVn pin enables the BPV counter, which is in the line interface, to increment each clock it is
high.
The RDATn, ROHMIn and RLCVn signals are sampled at the rising edge of the reference clock signal if the clock
pin is not inverted; otherwise they are sampled at the negative edge. The RLCLKn clock pin is the clock reference
used for the RDATn, ROHMIn and RLCVn signals. The RDATn, ROHMIn and RLCVn pins can be inverted. Please