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Devide frequency into 3 using AHDL or Verilog HDL

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ThaiHoa

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If i want to get 8.33MHz frequency from 25MHz frequency, how can i do when I'm using AHDL or Verilog HDL :(
 

Hi,
simply an @always posedge clock block where you count an reg from 0 to 2 an then toggle clock_slow (clock_slow=~clock_slow).

Now you can use clock_slow as your 8Mhz Clock...

regards
salamander
 

salamander said:
Hi,
simply an @always posedge clock block where you count an reg from 0 to 2 an then toggle clock_slow (clock_slow=~clock_slow).

Now you can use clock_slow as your 8Mhz Clock...

...which isn't 8.33MHz at all but input frequency/6 (o;


...and if you weren't too lazy searching here in this forum you would have come up easily with:

Code:
// Divide by 3 module
//

module divide(
	CLK,
	DIV3
);

	input	CLK;
	output	DIV3;

	reg	cnt_a, cnt_b;
	
	always @ (posedge CLK)
	begin
		cnt_a <= ~cnt_a & ~cnt_b;
		
		cnt_b <= cnt_a;
	end

	assign	DIV3 = cnt_b;

endmodule
 

xilinx has a application noet on it.
u can generate many odd freq using it.
hock
 

I`m sorry for mistake :oops:

Clock Divider with 50/50 Duty
 

who can decompress the file?
i use winrar3.
 

I use winzip 9.0, and it can decompress it.
 

If you want to get any given frequency from a source you can use DDS (Direct Digital Synthisis.) That is if you dont have a PLL already. I assume that you are using Altera parts as you mention AHDL if you have a cyclone then there should be some PLLs on board so problem solved.
DDS has the problem of phase jitter these numbers would have some serious jitter problems I think.
 

there is a pdf fine from st micro-electronics. That is an excellent note on how to divide clock with 50% duty cycle and you can divide with odd numbers also. search net for pdf file st clock divider. this is patented one.
 

silencer3 said:
there is a pdf fine from st micro-electronics. That is an excellent note on how to divide clock with 50% duty cycle and you can divide with odd numbers also. search net for pdf file st clock divider. this is patented one.

Where PDF :?:
 

Here are two pdf files for unusual clock dividers : excellen

download the tar file and install. you get two pdf files giving excellent clock dividing methods


enjoy
 

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