Altera Integer Arithmetic IP Bedienungsanleitung PDF herunterladen (Seite 23)

Port Name Required Description

eq[15..0] No Counter decode output. The eq[15..0] port is not accessible

using the MegaWizard Plug-In Manager as it is for AHDL use

only.

Either the q[] port or eq[] port must be connected. Up to c eq

ports can be used (0 <= c <= 15). Only the 16 lowest count values

are decoded. When the count value is c, the eqc output is asserted

high (1). For example, when the count is 0, eq0 = 1, when the

count is 1, eq1 = 1, and when the count is 15, eq 15 = 1. Decoded

output for count values of 16 or greater require external decoding.

The eq[15..0] outputs are asynchronous to the q[] output.

cout No Carry-out port of the counter's MSB bit. It can be used to connect

to another counter to create a larger counter.

Parameters

The following table lists the parameters for the LPM_COUNTER megafunction.

Table 2-4: LPM_COUNTER Megafunction Parameters

Parameter Name Type Required Description

LPM_WIDTH Integer Yes Specifies the widths of the data[] and q[]

ports, if they are used.

LPM_DIRECTION String No Values are UP, DOWN, and UNUSED. If the LPM_

DIRECTION parameter is used, the updown

port cannot be connected. When the

updown port is not connected, the LPM_

DIRECTION parameter default value is UP.

LPM_MODULUS Integer No The maximum count, plus one. Number of

unique states in the counter's cycle. If the

load value is larger than the LPM_MODULUS

parameter, the behavior of the counter is

not specified.

LPM_AVALUE Integer/

String

No Constant value that is loaded when aset is

asserted high. If the value specified is larger

than or equal to <modulus>, the behavior of

the counter is an undefined (X) logic level,

where <modulus> is LPM_MODULUS, if

present, or 2 ^ LPM_WIDTH. Altera

recommends that you specify this value as a

decimal number for AHDL designs.

LPM_SVALUE Integer/

String

No Constant value that is loaded on the rising

edge of the clock port when the sset port is

asserted high. Altera recommends that you

specify this value as a decimal number for

AHDL designs.

UG-01063

2014.12.19

Parameters

2-5

LPM_COUNTER (Counter)

Altera Corporation

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