AN 661: Implementing Fractional PLL Reconfiguration with Altera PLL and Altera PLL Reconfig IP Cores

ID 683640
Date 10/14/2019
Public
Document Table of Contents

1.2.1.2. Dynamic Phase Shift Signals in Altera PLL IP Core

Table 6.  Dynamic Phase Shift Signals in Altera PLL IP Core
Port Direction Description
phase_en Input Transition from low to high enables dynamic phase shifting, one phase shift per transition from low to high.
scanclk Input Free running clock from the core in combination with phase_en to enable and disable dynamic phase shifting.
updn Input Selects dynamic phase shift direction; 1= positive phase shift; 0 = negative phase shift. The PLL registers the signal on the rising edge of scanclk.
cntsel Input Logical Counter Select5 6. Five bits decoded to select one of the C counters for phase adjustment. The PLL registers the signal on the rising edge of scanclk.
phase_done Output When asserted, this port informs the core-logic that the phase adjustment is complete and the PLL is ready to act on a possible next adjustment pulse. Asserts based on internal PLL timing. Deasserts on the rising edge of scanclk.
5 For the corresponding address of a selected logical counter, refer to the Logical Counter Bit Setting table .
6 For the Intel® Quartus® Prime software versions prior to 13.1, cntsel refers to physical counter. For the Intel® Quartus® Prime software version 13.1 and later, cntsel refers to logical counter. Refer to the Logical Counter Bit Setting table for the cntsel bit setting for both physical counter and logical counter.