Altera Phase-Locked Loop (Altera PLL) IP Core User Guide

ID 683359
Date 6/16/2017
Public

Ports

Table 9.   Altera PLL Ports
Port Name Type Condition Description
fbclk Input Optional

The external feedback input port for the PLL.

The Altera PLL IP core creates this port when the PLL is operating in external feedback mode or zero-delay buffer mode. To complete the feedback loop, a board-level connection must connect the fbclk port and the external clock output port of the PLL.

fboutclk Output Optional

The port that feeds the fbclk port through the mimic circuitry.

The fboutclk port is available only if the PLL is in external feedback mode.

locked Output Optional

The Altera PLL IP core drives this port high when the PLL acquires lock. The port remains high as long as the PLL is locked.

The PLL asserts the locked port when the phases and frequencies of the reference clock and feedback clock are the same or within the lock circuit tolerance. When the difference between the two clock signals exceeds the lock circuit tolerance, the PLL loses lock.

outclk[] Output Required The clock output of the PLL. The frequency of the output clock depends on the parameter settings.
refclk Input Required The reference clock that drives the clock network.
reset Input Required The asynchronous reset port for the output clocks. Drive this port high to reset all output clocks to the initial value of 0.
zdbfbclk Bidirectional Optional

The bidirectional port that connects to the mimic circuitry. This port must connect to a bidirectional pin that is placed on the positive feedback dedicated output pin of the PLL.

The zdbfbclk port is available only if the PLL is in zero-delay buffer mode.

refclk1 Input Required Second input clock signal that feeds into the PLL.
extswitch Input Required Assert this input signal high (1’b1) to manually switch the clock for at least 3 cycles.
activeclk Output Optional Output signal to determine which input clock is in use by the PLL.
clkbad Output Optional Output signal to determine which input clock is working.
cclk 8 Input Optional C-Counter clock source from the fracturable fractional PLL output counter 4 or 13.
adjpllin Input Optional Adjacent fractional PLL clock source.
cascade_out Output Optional Output signal to feed into other fractional PLLs. This port acts as a bus port when the upstream PLL has two or more output clocks.
8 Not supported in Cyclone® V devices.