4.2.8 LPM_DECODE

 

Copyright © 1998 University of Manchester

Ports
Port Name
Type
Usage
Description Comments
Data
I
Required
Data input. Treated as unsigned binary number. Vector, LPM_Width wide
Enable
I
Optional
Enable. All outputs low when not active Default value is Active (High) if absent.
EQ
O
Required
For i = 0 to LPM_Decodes

if (i = Data) Eqi = 1

else Eqi = 0

Vector, LPM_Decodes wide.

If Data > = LPM_Decodes then all

Eqi are 0

Clock
I
Optional
Clock for pipelined usage Note 1
Aclr
I
Optional
Asynchronous Clear Note 2

Note 1: The clock port provides for pipelined operation of the LPM_MUX. If a latency other 0 (default value) is specified, then the clock port must be connected.

Note 2: The pipelined initializes to undefined. The Aclr port may be used at any time to reset the pipeline to all 0's asynchronously to clock.

Properties
Property
Usage
Value Comments
LPM_Width
Required
LPM Value > 0Width of input vector
LPM_Decodes
Required
0 < LPM Value < = 2LPM_Width Number of explicit decodes
LPM_Pipeline
Optional
LPM Value > = 0Default is 0 - non-pipelined

Functions
Enable
Data vector
Eqi that is 1 (high)

all other Eqi = 0 (low)
L
X
NONE
H
0000...000
Eq0
H
0000...001
Eq1
...
...
...
H
0000...101
Eq5
...
...
...
H
Data = LPM_Decodes -1
Eq(LPM_Decodes-1)
H
Data = LPM_Decodes
NONE
H
Data > LPM_Decodes
NONE

Note 1: If Data = i and Eqi is not connected or does not appear in the symbol then all outputs will be low.