Altera Phase-Locked Loop User Manual
Page 4
Parameter
Legal Value
Description
Desired Frequency
(1)
—
Specifies the output clock frequency of the corresponding
output clock port,
outclk[]
, in MHz. The default value is
100.0 MHz. The minimum and maximum values depend on
the device used. The PLL only reads the numerals in the first
six decimal places.
Actual Frequency
—
Specifies the actual value for the output clock frequency.
Phase Shift units
ps or degrees Specifies the phase shift unit for the corresponding output
clock port,
outclk[]
, in picoseconds (ps) or degrees.
Phase Shift
—
Specifies the requested value for the phase shift. The default
value is 0 ps.
Actual Phase Shift
—
Specifies the actual value for the phase shift.
Duty Cycle
1–99
Specifies the duty cycle in percentage for the corresponding
output clock port,
outclk[]
. The default value is 50%.
Fractional carry out
(2)(3)
8, 16, 24, or 32 Specifies the fractional carry out (
Fcout
) for the Delta Sigma
Modulator (DSM) mode for PLL. The fractional carry out
determines the denominator in the equation K/2^
Fcout
.
DSM Order
(2)(3)
1st_order,
2nd_order,
3rd_order, or
disable
Specifies the DSM order for shifting the fractional noise to
be filtered out by the PLL to high frequencies.
Multiply Factor (M-
Counter)
(3)
1-512
Specifies the multiply factor of
M
-counter.
Fractional Multiply Factor
(K)
(2)(3)
1 to (2^
Fcout
-
1)
Specifies the fractional multiply factor of DSM.
Fcout
is the
value of fractional carry out parameter.
Divide Factor (N-
Counter)
(3)
1-512
Specifies the divide factor of
N
-counter.
Make this a cascade
counter
(3)(4)
Turn on or
Turn off
Turn on to cascade this counter into the next counter
output for larger division factor.
Divide Factor (C-
Counter)
(3)
1-512
Specifies the divide factor for the output clock (
C
-counter)
Altera PLL IP Core Parameters - Clock Switchover Tab
Table 2: Altera PLL IP Core Parameters - Clock Switchover Tab
Parameter
Legal Value
Description
Create a second input clk
‘refclk1’
Turn on or
Turn off
Turn on to provide a backup clock attached to your PLL
that can switch with your original reference clock.
(1)
This parameter is only available when Enable physical output clock parameters is turned off.
(2)
This parameter is only available in Fractional-N PLL mode.
(3)
This parameter is only available when Enable physical output clock parameters is turned on.
(4)
This feature is only supported in Quartus
®
II version 13.1 and onwards.
4
Altera PLL IP Core Parameters - Clock Switchover Tab
UG-01087
2015.05.04
Altera Corporation
Altera Phase-Locked Loop (Altera PLL) IP Core User Guide