Specifications
Table 3–3. Encoder Signals (Part 2 of 2)
Signal Name
idle_ins
Direction
Description
Input
Idle character insert. When high, idle (K28.5) characters are inserted
when enais not asserted.
Input
Input
Data input. This is the 8-bit input word, data or command.
datain[7:0]
rdin
Running disparity input. When rdforceis high, the value on this pin is
used as the current running disparity instead of the internally generated
one.
Input
rdforce
kerr
Force running disparity. When high, the rdinvalue overrides the
internally generated running disparity.
Output
Special K character error. This signal is set high when enaand kinare
high and the value on datainis not a valid special K character.
Output
Output
Data output. This is the 10-bit encoded output.
dataout[9:0]
valid
Valid signal. When high, indicates that a valid encoded word is present
on the dataoutoutput.
Output
Output
Running disparity output. The current running disparity (after encoding
the word present on the dataoutoutput).
rdout
Cascaded running disparity. Used when encoders are cascaded.
rdcascade
Table 3–4. Decoder Signals (Part 1 of 2)
Signal Name
Direction
Description
Input
Clock. The input is latched, and the result output on this clock. There is
a three clock cycle latency between the input and output.
clk
Input
Active low, reset. Asynchronously resets all registers in the MegaCore
function. This signal must be deasserted synchronously to the rising
edge of clk.
reset_n
Input
Input
Idle delete signal. When high, idle words (K28.5) are removed from the
stream (i.e. validis set low when idle words are received).
idle_del
ena
Enable decoder signal. When high, indicates that the data currently
present on the dataininput is to be decoded.
Input
Input
Data input. This is the 10-bit encoded input word.
datain[9:0]
rdin
Running disparity input. When rdforceis high, the value on this pin is
used as the current running disparity instead of the internally generated
one.
Input
rdforce
Force running disparity. When high, the rdinvalue overrides the
internally generated running disparity.
Altera Corporation
October 2007
MegaCore Version 7.2
3–11
8B10B Encoder/Decoder MegaCore Function User Guide
ALTERA [ ALTERA CORPORATION ]
