Maximum output PWM frequency from Altera Cyclone IV?

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rockgro

Joined Sep 7, 2021
15
If I want to generate PWM signals using Altera Cyclone IV FPGA then what is the maximum frequency I can get?

I am planning to use an FPGA to generate 12 digital outputs, then feed it to a 12bit DAC to get an analog output (Signal generator using FPGA)
 

Papabravo

Joined Feb 24, 2006
18,964
That information would be in the datasheet. Do you have the datasheet, or were you hoping someone had the answer of the top of their head?
How were you planning to generate the PWM signals?
 

ronsimpson

Joined Oct 7, 2019
2,242
I think you want to know how fast you can run a 12bit counter. ?? Build one and let the tools tell you max speed.

Back when I did this, the tools were not as good. I had to force the counters into rectangles and place the blocks around the outside of the part. Then lock down the parts to the compiler could not move them. I needed to have consistent timing from PWM to IO pin.

There are many different ways to make PWM in a FPGA. If you need more speed come back and show how you are doing it.
 

JWHassler

Joined Sep 25, 2013
297
If I want to generate PWM signals using Altera Cyclone IV FPGA then what is the maximum frequency I can get?

I am planning to use an FPGA to generate 12 digital outputs, then feed it to a 12bit DAC to get an analog output (Signal generator using FPGA)
Are you driving DACs or generating PWM? The two seem mutually exclusive.
 

Papabravo

Joined Feb 24, 2006
18,964
I want to generate 12bit digital output from FPGA which then I will provide to a 12BIT DAC to get analog output
So basically, you have no idea how to generate a PWM signal, either by analog means or by digital means.
Maybe it would be better for you to go back to first principles and discover the various ways of generating a PWM signal so you would have some basis for answering your own question.
 

Papabravo

Joined Feb 24, 2006
18,964
From what he has said, there is no PWM signal involved. It is probably just a buzzword he heard somewhere.
I'm not entirely certain that is the case. There are many general misunderstandings of the what and the how of PWM generation and control. This may be one of them, or it may be as you say unrelated.
 

ronsimpson

Joined Oct 7, 2019
2,242
I am planning to use an FPGA to generate 12 digital outputs, then feed it to a 12bit DAC to get an analog output
Lets start over. Forget "PWM".

I think you want an analog voltage from a DAC.
At 12 bits I see DACs that will work in the 100mhz to 500mhz speed range. The 100mhz parts are simple. For fast parts you will need to send differential LVDS data. I am looking at this part. DAC3162

I have not looked at how fast your FPGA works. I have boards in my lab that update the DAC at 500mhz. Not an easy task.
If this is you first try, you should start out at 100mhz or slower.
 
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