
26
Altera Corporation
Storage Functions
lpm_ff
Parameterized D or T Flipflop
Ports
Name
Type
Required
Description
aload
Input
No
Asynchronous load input. Asynchronously loads the flipflop with the value on
the
data[]
input. Default = 0. If
aload
is used,
data[]
must be used.
Synchronous set input. Sets the
q[]
outputs to the value specified by
LPM_SVALUE
, if that value is present, or sets the
q[]
outputs to all 1s. If both
sset
and
sclr
are used and both are asserted,
sclr
is dominant. The
sset
input affects the output
q[]
values before polarity is applied to the ports.
Synchronous load input. Loads the flipflop with the value on the
data[]
input
on the next active clock edge. Default = 0. If
sload
is used,
data[]
must be
used. For load operation,
sload
must be high (1) and
enable
must be high
(1) or unconnected.
T flipflop: toggle enable; D flipflop: data input. This port is
LPM_WIDTH
wide. If
the
data[]
port is not used, at least one of the
aset
,
aclr
,
sset
, or
sclr
ports must be used.
Positive-edge-triggered clock.
Clock enable input. Default = 1.
Synchronous clear input. If both
sset
and
sclr
are used and both are
asserted,
sclr
is dominant. The
sclr
input affects the output
q[]
values
before polarity is applied to the ports.
Asynchronous set input. Sets
q[]
outputs to the value specified by
LPM_AVALUE
, if that value is present, or sets the
q[]
outputs to all 1s.
Asynchronous clear input. If both
aset
and
aclr
are used and both are
asserted,
aclr
is dominant. The
aclr
input affects the output
q[]
values
before polarity is applied to the ports.
Data output from D flipflops. This port is
LPM_WIDTH
wide.
sset
Input
No
sload
Input
No
data[]
Input
No
clock
Input
Input
Input
Yes
No
No
enable
sclr
aset
Input
No
aclr
Input
No
q[]
Output
Yes
aload
sset
sload
data[]
clock
enable
sclr
LPM_FF
LPM_AVALUE=
LPM_FFTYPE=
LPM_SVALUE=
LPM_WIDTH=
q[]
aclr
aset