LPC54xx: Control fan with rpm

[sergiobiasi]

Hello,

I'm using LPC54606 to speed up four fans with PWM. Three fans have feedback rpm and I'm trying to read these.

I wished to use SCTIMER for all the job but found that each PWM uses two events so I consume 8 events to move (indipendently) the four fans.

I'm quite new to SCTimer so maybe I'm missing something. For example, can I use one event common to all PWM and the other one for the duty cycle of the single PWM? In this case I could free three events.

If this is not possible, I see LPC has also CTIMER functionality but I've not found any significant example/application note to handle. Some hints?

Note that I'm using MCUXpresso 11 to configure the peripherals. Maybe there are some limitations compared to write code "by hand".

Thanks for your support.

[jeremyzhou]

Hi Sergio Biasi,

Thank you for your interest in NXP Semiconductor products and
for the opportunity to serve you.
I think I need to get more information about your question prior to give some suggestions or solutions, so I was wondering if you can draw or introduce what exactly PWM output you want to make.
Looking forward to your reply.

Have a great day,
TIC

-------------------------------------------------------------------------------
Note:
- If this post answers your question, please click the "Mark Correct" button. Thank you!

- We are following threads for 7 weeks after the last post, later replies are ignored
Please open a new thread and refer to the closed one, if you have a related question at a later point in time.
-------------------------------------------------------------------------------

[sergiobiasi]

Hi Jeremy,

sorry if I was not clear in my first post.

Actually PWM outputs are correct and the fans rotate indipendently at

different rotation speed.

What I need is a control on the rotation feedback. Each fan returns a pulse

signal when they rotate, I have to check that it's "compatible" with the

speed requested. If a fan has a fail or is broken, it must be reported.

I realized that there are insufficient events in the SCTimer (MCUXpresso

complains when I add more than two events), so I was asking if there is a

way to use only five events to generate four indipendent PWM outputs.

Thanks again and best regards,

Sergio

Il presente messaggio e-mail e ogni suo allegato devono intendersi indirizzati esclusivamente al destinatario indicato e considerarsi dal contenuto strettamente riservato e confidenziale. Se non siete l'effettivo destinatario o avete ricevuto il messaggio e-mail per errore, siete pregati di avvertire immediatamente il mittente e di cancellare il suddetto messaggio e ogni suo allegato dal vostro sistema informatico. Qualsiasi utilizzo, diffusione, copia o archiviazione del presente messaggio da parte di chi non ne è il destinatario è strettamente proibito e può dar luogo a responsabilità di carattere civile e penale punibili ai sensi di legge.

Questa e-mail ha valore legale solo se firmata digitalmente ai sensi della normativa vigente.

The contents of this email message and any attachments are intended solely for the addressee(s) and contain confidential and/or privileged information.

If you are not the intended recipient of this message, or if this message has been addressed to you in error, please immediately notify the sender and then delete this message and any attachments from your system. If you are not the intended recipient, you are hereby notified that any use, dissemination, copying, or storage of this message or its attachments is strictly prohibited. Unauthorized disclosure and/or use of information contained in this email message may result in civil and criminal liability. “

This e-mail has legal value according to the applicable laws only if it is digitally signed by the sender

[jeremyzhou]

Thanks for your clarification.
1) I realized that there are insufficient events in the SCTimer (MCUXpresso complains when I add more than two events), so I was asking if there is a way to use only five events to generate four independent PWM outputs.
-- Yes, it's available to generate four independent PWM outputs with utilizing the five events if these PWMs share a common period.
I've attached an application note which is a collection of examples and usage notes for the SCTimer/PWM block used in NXP microcontrollers, please refer to it for details.

Have a great day,
TIC

-------------------------------------------------------------------------------
Note:
- If this post answers your question, please click the "Mark Correct" button. Thank you!

- We are following threads for 7 weeks after the last post, later replies are ignored
Please open a new thread and refer to the closed one, if you have a related question at a later point in time.
-------------------------------------------------------------------------------

[sergiobiasi]

Hi Jeremy,

thanks for your answer, that's what I was looking for.

About application note, I don't see any attachment but if you intended the AN11538 I already got it.

Best regards.

[jeremyzhou · Accepted solution]

Hi Sergio Biasi,

Thanks for your reply.
I had already attached the AN11538 before, whereas they are invisible to you, it seems a bit weird.
Fortunately, you already got it.

Have a great day,
TIC

-------------------------------------------------------------------------------
Note:
- If this post answers your question, please click the "Mark Correct" button. Thank you!

- We are following threads for 7 weeks after the last post, later replies are ignored
Please open a new thread and refer to the closed one, if you have a related question at a later point in time.
-------------------------------------------------------------------------------