Conflict in Fan Controller Datasheet?

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bralc_4237001
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Hello

I see what may be a conflict in the Fan Controller datasheet where manual mode seems to suggest only the ability to use the PWM Duty cycle API and there is no response to fan speed, but a graphic further down in the sheet seems to imply that the desired fan speed API can be used in manual mode.

So I really need a clarification, before I start writing code.

Thanks

A_Cypress_PWM.JPG

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Aashita_R
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50 likes received 100 solutions authored 250 replies posted

Hi @bralc_4237001 ,

I read through the component datasheet to understand the issue you are pointing at. As mentioned in the datasheet that in the manual mode i.e. open loop control mode, the SetDutyCycle() API is used to set the PWM output duty cycle.  However, the SetDesiredSpeed() API sets the the desired speed of the specified fan in revolutions per minute (RPM). We acknowledge that there might be some missing information, regarding the addition of SetDesiredSpeed() API for the illustration of open loop control mode in the block diagram. I will update in this thread, once I get information from our internal team on this. Thank you for  your interest in Cypress products.

Meanwhile, Can you please follow the code example which I have attached here?  In this code example, the SetDesiredSpeed() API is used to set the desired speed of the fan at the initial RPM value. Thereafter, the SetDutyCycle() is used to then set the duty cycle for the output PWM, after fine tuning the duty cycle finally.

Please go through this and let us know if this helps or in case of further clarifications.

Best Regards,

Aashita

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Aashita_R
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50 likes received 100 solutions authored 250 replies posted

Hi @bralc_4237001 ,

I read through the component datasheet to understand the issue you are pointing at. As mentioned in the datasheet that in the manual mode i.e. open loop control mode, the SetDutyCycle() API is used to set the PWM output duty cycle.  However, the SetDesiredSpeed() API sets the the desired speed of the specified fan in revolutions per minute (RPM). We acknowledge that there might be some missing information, regarding the addition of SetDesiredSpeed() API for the illustration of open loop control mode in the block diagram. I will update in this thread, once I get information from our internal team on this. Thank you for  your interest in Cypress products.

Meanwhile, Can you please follow the code example which I have attached here?  In this code example, the SetDesiredSpeed() API is used to set the desired speed of the fan at the initial RPM value. Thereafter, the SetDutyCycle() is used to then set the duty cycle for the output PWM, after fine tuning the duty cycle finally.

Please go through this and let us know if this helps or in case of further clarifications.

Best Regards,

Aashita

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Thank you for your consideration on this issue.

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