DPLL Primitive

Versal ACAP Clocking Resources Architecture Manual (AM003)

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1.4 English

The VersalĀ® device DPLL instantiable primitive is shown in the following figure.

Figure 1. DPLL Primitive

The DPLL is a digital block designed to support clock network deskew, frequency synthesis, and jitter reduction. These three modes of operation are discussed in more detail in this section. The DCO operating frequency can be determined using the following relationship:

where the M, D, and O counters are shown in Figure 1. The value of M corresponds to the CLKFBOUT_MULT_F setting, the value of D to the DIVCLK_DIVIDE, and O to the CLKOUT_DIVIDE.

The four O counters can be independently programmed. For example, O0 can be programmed to do a divide-by-two while O1 is programmed for a divide-by-three. The only constraint is that the VCO operating frequency must be the same for all the output counters because a single VCO drives all the counters.