S2042 AMCC (Applied Micro Circuits Corp), S2042 Datasheet - Page 4

• Manufacturer Part Number: S2042
• Description: High Performance Serial Interface Circuits
• Manufacturer: AMCC (Applied Micro Circuits Corp)

S2043 RECEIVER FUNCTIONAL
DESCRIPTION
The S2043 receiver is designed to implement the
ANSI X3T11 Fibre Channel specification receiver
functions. A block diagram showing the basic chip
function is provided in Figure 4.
Whenever a signal is present, the S2043 attempts to
achieve synchronization on both bit and transmis-
sion-word boundaries of the received encoded bit
stream. Received data from the incoming bit stream
is provided on the device’s parallel data outputs.
The S2043 accepts serial encoded data from a fiber
optic or coaxial cable interface. The serial input stream
is the result of the serialization of 8B/10B encoded
data by an FC compatible transmitter. Clock recov-
ery is performed on-chip, with the output data
presented to the Fibre Channel transmission layer
as 10- or 20-bit parallel data. The chip is program-
mable to operate at the Fibre Channel specified
operating frequencies of 1062, 531 and 266 Mbit/s.
Serial/Parallel Conversion
Serial data is received on the RX, RY pins. The PLL
clock recovery circuit will lock to the data stream if the
clock to be recovered is within 100 PPM of the inter-
nally generated bit rate clock. The recovered clock is
Figure 5. Functional Waveform
4
S2042/S2043
S
2
0
4
2
S
2
0
4
3
Table 3. Data Mapping to 8b/10b Alphabetic Representation
PARALLEL
DATA BUS
(Output)
TX[00:19] or
RX[00:19]
8b/10b alphabetic
representation
REFCLK
(Input)
SERIAL DATA
RCLK
(Output)
SYNC
(Output)
PARALLEL
DATA BUS
(Input)
0
a
Byte 1
of Data
K28.5,
First bit received in 20-bit mode
1
b
Byte 2, 3
of Data
2
c
First Data Byte
3
d
K28.5
Byte 4, 5
of Data
HIGH PERFORMANCE SERIAL INTERFACE CIRCUITS
4
e
D1
D2
5
i
Byte 6, 7
of Data
of Data
Byte 1
K28.5,
D3
6
f
D4
Byte 8, 9
of Data
7
g
Byte 2, 3
D5
of Data
8
h
used to retime the input data stream. The data is
then clocked into the serial to parallel output regis-
ters on the low going edge of RCLK. In 1062 Mbit/
sec, 10-bit mode, data is clocked out on the falling
edge of RCLK and RCLKN.The parallel data out can
be either 10 or 20 bits wide determined by the state
of the DWS pin. The word clock (RCLK) is synchro-
nized to the incoming data stream word boundary by
the detection of the fiber channel K28.5 synchroniza-
tion pattern (0011111010, positive running disparity).
10-Bit/20-Bit Mode
The S2043 will operate with either 10-bit or 20-bit
parallel data outputs. This option is selectable via
the DWS pin. See Table 4. In 10-bit mode, D10-D19
are used and D0-D9 are driven to the logic high state.
Reference Clock Input
The reference clock input must be supplied with a single-
ended AC coupled crystal clock source at 100 PPM
tolerance. See Table 4 for reference clock frequencies.
Framing
The S2043 provides SYNC character recognition and
data word alignment of the TTL level compatible output
data bus. In systems where the SYNC detect function
is undesired, a LOW on the SYNCEN input disables
the SYNC function and the data will be “un-framed”.
D6
11 of Data
Byte 10,
9
j
Byte 4, 5
D7
of Data
10
a
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13 of Data
D8
Byte 12,
First bit received in 10-bit mode
Byte 6, 7
11
of Data
D9
b
Byte 14,15
D10
12
of Data
c
Byte 8, 9
D11
of Data
Second Data Byte
13
d
D12
Byte 16
of Data
K28.5
14
e
11 of Data
D13
Byte 10,
Applied Micro Circuits Corporation
15
i
D14
16
13 of Data
D15
f
Byte 12,
K28.5 D16
17
g
Byte 14,15
of Data
18
h
19
j