S2078
Serial-to-Parallel Conversion
Once bit synchronization has been attained by the
S2078 CRU, the S2078 must synchronize to the 10
bit word boundary. Word synchronization in the
S2078 is accomplished by detecting and aligning to
the 8B/10B K28.5 codeword. The S2078 will detect
and byte-align to either polarity of the K28.5. Each
channel of the S2078 will detect and align to a K28.5
anywhere in the data stream. The presence of a
K28.5 is indicated for each channel by the assertion
of the COM_DETx (Comma Detect) signal.
DUAL FIBRE CHANNEL TRANSCEIVER
Parallel Output Clock Rate
Two output clock modes are supported. When
CMODE is HIGH, a complementary TTL clock at the
data rate is provided on the RBC1/0x outputs. Data
should be clocked on the rising edge of RBC1x.
When CMODE is LOW, the S2078 outputs a
complementary TTL clock at 1/2 the data rate in
compliance with the the Fibre Channel 10 Bit Inter-
face Specification. Data should be latched on the
rising edge of RBC1x and the rising edge of RBC0x.
If consecutive K28.5 characters are received, the
S2078 RBC1/0x clock operates without glitches or
loss of cycles.
Data Output
Data is output on the DOUTx[0:9] outputs. The
COM_DETx signal is used to indicate the reception
of a valid K28.5 character and is driven concurrent
with the K28.5 character on the DOUTx[0:9] outputs.
The S2078 TTL outputs are optimized to drive 65Ω
line impedences. Internal source matching provides
good performance on unterminated lines of reason-
able length.
Table 4. Output Clock Modes
Mode
Half Clock Mode
Full Clock Mode
CMODE
0
1
RBC1/0x Freq.
53.125 MHz
1062.5 MHz
8
October 13, 2000 / Revision D
AMCC [ APPLIED MICRO CIRCUITS CORPORATION ]
