VSC6134
Datasheet
The TAP controller architecture is shown in the following figure.
Figure 76. TAP Controller Architecture
Instruction Shift & Hold
TDI
Registers
TDO
MUX
TDO
IDCODE Register
DFF
BYPASS Register
TCK
TMS
TAP Controller
State Machine
TRSTN
2.17.7
Word Swap Function
The VSC6134 supports a 16-bit word swap function on the Tx and Rx client side ports. This function
allows for the different bit and byte transmission order between the IEEE and IETF standards for
Ethernet data, and ITU conventions for SDH and OTN formats. Depending on the type of PHY
serializer/deserializer, first serial bit is assigned to either bit 15 (for SONET) or bit 0 (for Ethernet) of
the SFI-4 16-bit bus. The VSC6134 internal 16/64 bit seriaizer/deserializer always treats bit 15 as MSB
and bit 0 as LSB.
When the word swapping function is enabled (DROP_WORD_SWAP_EN on the client Tx port and
ADD_WORD_SWAP_EN on the client Rx port), bit order for each of the four 16-bit sequences in a
64-bit word is swapped from LSB to MSB. For example, Data_in(63) is mapped to
Data_in_swapped(48), Data_in(62) is mapped to Data_in_swapped(49), and so on. This swapping
function is illustrated in the following figure.
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VMDS-10185 Revision 4.0
July 2006
VITESSE [ VITESSE SEMICONDUCTOR CORPORATION ]
