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

[NS81]

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,

[n_scott_pearson]

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]

Dear n_scott_pearson，

Thank you for your response.

I will wait for the answer.

regards,

NS81

[n_scott_pearson]

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

...S

[NS81]

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]

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]

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]

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 · Accepted solution]

Dear n_scott_pearson，

I understood.

Thank you for your support.

Regards,

NS81