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Divider==Counter? How to divide by different "N"?

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knack

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Hi there!

Is it alway could stated that Counter = Divider and Divider = Counter??

I specially mean in PLL way back from VCO... the "÷N" block, is it counter or divider??

It should be multimodulus right?? for an application like a freq. Synthesizer!

Well, practically speaking, how can a counter or a divider be changed??

I assume that they'll change it using "clear" and "reset" etc. signals, but this will have different delays for divided signals...

Anybody understanding "how a multimodulus divider work" can explain it to me??

Cheers,

-- Knack
 

You can think of a divider as a counter that pulses a single bit output 'high' whenever the count value is 0x0. Then you build a counter that counts up (or down) to (from) a programmable value, wraps and keeps counting. Whenever it wraps, the output is pulsed high for a cycle. This will give you a multi-modulus N or M divider. For a post divider this approach is generally not sufficient because of the highly distorted duty cycle at the output.
 

    K

    knack

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Re: Divider==Counter? How to divide by different "N&amp

Yeah.. You're great!

But practically, how can i get a contineous range of values of N or M values that divider divide by them?

Can you provide sample simple example of such a divider? that may divide for example by values from 180-280 with constant unity step!.. is there something practically like that??

Thnx again :)
--Knack
 

In verilog for 16 bit divider (1-65536):

input CLK;
input [15:0] N;

output DIV_CLK;
reg DIV_CLK;
reg [15:0] counter;

always @(posedge CLK) begin
if(counter == N) counter <= 16'h0000;
else counter <= counter + 1'b1;
DIV_CLK <= (counter == 16'h0000);
end
 

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    knack

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Re: Divider==Counter? How to divide by different "N&amp

eternal_nan, How can i thank u!

But i don't have license to verilog, i have one to Verilog-A only!!! Your code can't be applied to it..

Moreover, i hope to get a block diagram to the divider or a Flip-Flop level schematic or something like that..

Thnx anyway
-- Knack
 

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