Agilex™ 7 Clocking and PLL User Guide: F-Series and I-Series

ID 683761
Date 8/21/2024
Public
Document Table of Contents

5.5. IOPLL IP Core Ports and Signals

Table 14.   IOPLL IP Core Ports for F-Series and I-Series Devices
Port Name Type Condition Description
refclk Input Required The reference clock source that drives the I/O PLL.
rst Input Required The asynchronous reset port for the output clocks. Drive this port high to reset all output clocks to the value of 0.
fbclk Input Optional

The external feedback input port for the I/O PLL.

The IOPLL IP core creates this port when the I/O 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 I/O PLL.

fboutclk Output Optional

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

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

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 I/O PLL.

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

locked Output Optional The IOPLL IP core drives this port high when the PLL acquires lock. The port remains high as long as the I/O PLL is locked. The I/O 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 I/O PLL loses lock.
refclk1 Input Optional Second reference clock source that drives the I/O PLL for clock switchover feature.
extswitch Input Optional Active low signal. Assert the extswitch signal low (1’b0) for at least three clock cycles to manually switch the clock.
activeclk Output Optional Output signal to indicate which reference clock source is in used by I/O PLL.
clkbad Output Optional Output signal that indicates the status of reference clock source is good or bad.
cascade_out Output Optional Output signal that feeds into downstream I/O PLL.
adjpllin Input Optional Input signal that feeds from upstream I/O PLL.
outclk_[] Output Optional Output clock from I/O PLL.
permit_cal Input Optional This is an input port for the downstream I/O PLL. Connect this permit_cal port to the locked output port of the upstream I/O PLL. Connecting this permit_cal port ensures that the cascaded I/O PLLs are calibrated in the correct order.
scanclk Input Optional

Dynamic phase shift clock that drives the IOPLL IP core dynamic phase shift operation. This port must be connected to a valid clock source. The maximum input clock frequency is 100 MHz.

The scanclk port is available only if the option of enable access to dynamic phase shift ports is turned on.

phase_en Input Optional

Active high signal. Asserts to start the dynamic phase shift operation. phase_en can only be asserted 4 clocks after phase_done assertion.

The phase_en port is available only if the option of enable access to dynamic phase shift ports is turned on.

updn Input Optional

Determines the direction of dynamic phase shift. When updn = 0, phase shift is in negative direction. When updn = 1, phase shift is in positive direction.

The updn port is available only if the option of enable access to dynamic phase shift ports is turned on.

cntsel[4..0] Input Optional
Determines the counter to be selected to perform dynamic phase shift operation.
Counter Name cntsel[4..0]
Counter C1 4’b0001
Counter C2 4’b0010
Counter C3 4’b0011
Counter C4 4’b0100
Counter C5 4’b0101
Counter C6 4’b0110
Counter C7 4’b0111
All C Counters 4’b1111

The cntsel[4..0] port is available only if the option of enable access to dynamic phase shift ports is turned on.

num_phase_shift[2..0] Input Optional

Determines the number of phase shifts per dynamic phase shift operation. Up to seven phase shifts per operation are possible. Each phase shift step is equal to 1/8 of I/O PLL VCO period. num_phase_shift must never be set to 0 in DPS mode.

The num_phase_shift [2..0] port is available only if the option of enable access to dynamic phase shift ports is turned on.

phase_done Output Optional

The IOPLL IP core drives this port high for one scanclk cycle after dynamic phase shift operation is complete.

The phase_done port is available only if the option of enable access to dynamic phase shift ports is turned on.