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NUC11TNBi5 - Signal level of Serial Port Header (1.25mm pitch)

NS81
Novice
435 Views

Hello, Everyone.

We will use serial port to communicate with extra MCU.

So, we want to know the signal level of "Serial port Header" .

3.3V-TTL, 3.3V-CMOS, 5V-TTL, RS-232c...

Which level is needed??

 

Many thanks,

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1 Solution
NS81
Novice
264 Views

Dear n_scott_pearson,

 

I understood.

Thank you for your support.

 

Regards,

NS81

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8 Replies
n_scott_pearson
Super User Retired Employee
419 Views

I believe that it is 5V TTL, but there is a chance that it is only 3.3V TTL. I will endeavor to get a better answer from the dev. team, but they likely won't respond until at least Tuesday afternoon (PST) as Monday is a holiday in the U.S.

...S

NS81
Novice
418 Views

Dear n_scott_pearson,

 

Thank you for your response.

I will wait for the answer.

 

regards,

NS81

n_scott_pearson
Super User Retired Employee
358 Views

I was wrong. Their response: "The RS232 transceivers (ZT3243E) support both TTL/CMOS,  we use 3.3v CMOS."

...S

NS81
Novice
349 Views

 

Dear n_scott_pearson,

 

Thank you for your response.

 

Are you saying  "NUC's serial port need RS-232C Level." ??

I think we have to use RS-232C transceiver between serial port of NUC and (our) extra MCU, as shown in the figure below.

 

[NUC's serial port]-----(RS-232C level)-----[RS232 Transceiver]-----(UART level)-----[extra MCU] 

n_scott_pearson
Super User Retired Employee
334 Views

They are saying that the RS232 transceivers that they used support both TTL and CMOS I/O. They configure them for 3.3V CMOS I/O. If you want the standard +/- 12V signals, then yes, you are going to need to add something to achieve it.

...S

NS81
Novice
323 Views

Dear n_scott_pearson,

 

Thank you for your response.

In particular, I don't want the standard +/- 12V signals.

 

Can I connect 3.3V CMOS signal directly to the NUC serial port header ??

or

Does a NUC serial port header need standard RS232 signal level (+/-12V) ??

 

I'm trying to use NUC serial port header to communicate the NUC with an external CPU.

 

regards,

NS81

n_scott_pearson
Super User Retired Employee
281 Views

Yes, if the device on the other end also utilizes 3.3V CMOS signaling, then you can connect directly.

No, none of the NUCs offering serial ports support the standard RS232c +/-12V signal levels. If you had wanted that, the best approach would have been to go with a USB RS232c add-on.

...S

NS81
Novice
265 Views

Dear n_scott_pearson,

 

I understood.

Thank you for your support.

 

Regards,

NS81

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