Lattice Semiconductor Reed-Solomon Encoder User’s Guide
7
Figure 9 explains the timing of an RS (7,3) double-pipelined encoder with
start
re-asserted during the operation
of the encoder. The handshaking signal,
rdy
, indicates the encoder is ready to receive a new set of data when
start
is re-asserted during encoding.
Figure 9. Timing of an RS (7,3) Double Pipelined Encoder with
start
Re-asserted
Signal Definitions
Table 1 shows the input and output signals for the Reed-Solomon Encoder core. Refer to the
ispLEVER™ Software
User’s Manual
for additional information.
Table 1. Reed-Solomon Encoder Signals
Signal Name I/O Type
Active
State
Signal Description
d_in[s-1:0]
Input
N/A Input data
rstn
Input
Low Asynchronous reset input
enable
Input
High Enables the encoder to process data on
d_in
. When low, the input data is
ignored and
d_out
holds its state.
byp
Input
High Indicates the data on
d_in
should pass directly through to
d_out
after the
latency. This signal is ignored if
enable
is low.
start
Input High Indicates that the data on
d_in
is the first information symbol of a new code-
word.This signal is ignored if
byp
is high or enable is low.
clk
Input
Rising Edge Master clock input
d_out[s-1:0]
Output
N/A Output data
status
Output
High Indicates the information symbols are present on
d_out
or
byp
is asserted.
dvalid
Output
High Indicates valid data on
d_out
.Not available with continuous configuration
rdy
Output
High Indicates the encoder is ready to receive data.Active when
rstn
is asserted or
when ready to receive data or
start
is asserted. Inactive when sufficient data
has been received and check symbols are being calculated. Not available with
continuous configuration
X3 X2 X1X3
clk
rstn
start
enable
byp
d_in
D6 D5 D4
d_out
D6 D5 D4 D6 D5 D4C3
status
rdy
dvalid
D6 D5 D4
