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How to divide clock frequencies with digital logic?
Using and and or gates, you can effectively string together flip flop outputs to match your 50% duty cycle. Here’s a good paper with some examples, from a Xilinx engineer. Note that for this project, we divide our clock by 4, then 2 (so… 8). We then multiply by 14 to get around dividing by 4 and multiplying by 7.
How is a logic gate different from an electronic gate?
Electronic gates. The semiconductor logic gate, on the other hand, acts as a high- gain voltage amplifier, which sinks a tiny current at its input and produces a low-impedance voltage at its output. It is not possible for current to flow between the output and the input of a semiconductor logic gate.
What kind of gates are used in reversible logic?
In reversible logic, Toffoli gates are used. A functionally complete logic system may be composed of relays, valves (vacuum tubes), or transistors. The simplest family of logic gates uses bipolar transistors, and is called resistor–transistor logic (RTL).
What is the circuit architecture of a PFD?
CIRCUITS ARCHITECTURE The circuit consists of two resettable, edge triggered D flip flops with their D inputs tied to logic 1 and a NAND Gate in the reset path (fig.2). The explanation of the general operation of the PFD begins by describing the initial state of the device.
Why is clock latency not included in output delay?
By default the clock source latency of the related clock is added to the output delay value, but when the -source_latency_included option is specified, the clock source latency is not added because it was factored into the output delay value.
What does set output delay do in SDC?
By default, set_output_delay removes any other output delays to the port except for those with the same -clock, -clock_fall, and -reference_pin combination. Multiple output delays relative to different clocks, clock edges, or reference pins can be specified using the -add_delay option.
How to divide clocks by non-powers of two?
Note, too, that you can create very complex methods to divide clocks by non-powers of two. Using and and or gates, you can effectively string together flip flop outputs to match your 50% duty cycle. Here’s a good paper with some examples, from a Xilinx engineer.