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Altera_Forum
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15 years ago

Help-about peripheral IP design

Hi,dear friends. Recently I have done a DAC IP as a Nios peripheral but it doesn't meet the requirment.I do this IP as the example "pwm" from Altera.com.Now I send a series number to the dac(A...
Altera_Forum's avatar
Altera_Forum
Icon for Honored Contributor rankHonored Contributor
15 years ago

the resulting frequency at the output of your dac depends upon the speed you feed the dac with new values. the faster the cpu is and or its clock, the faster the while (1) loop will be executed the faster the dac gets its next value, hence the output frequency will increase.

but you will also get jitter, if the cpu is executing some kind of interupt and during that time cannot feed the dac with new values.

if you want to get rid of jitter and cpu dependencies. you should use hardware instead of software to feed your dac to provide a stable and well known updating frequency of your dac data.