How to use NF function of UART?

[hiroshinakata]

Hi. I have a question about UART function of Kinetis K61.

According to the datesheet, K61 have a NF(Noise Flag) function. So, I have a questions about Noise Flag Function.

1: What's the definition of noise? (What kind of input signal regard as noise?)

2:How to check whether Noise Flag function enable?

[Hui_Ma]

Hi,

1. The advanced sampling technique used in the receiver takes seven samples during the start bit and three samples in each data bit and the stop bit. If any of these samples disagrees with the rest of the samples within any bit time in the frame, the flag NF will be set.

2. It is hard to generate that error, customer could try to using a noise generator with UART RX pin to check if NF bit could be set.

Wish it helps.

Have a great day,
Ma Hui

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[hiroshinakata]

Thank you for your answer. I appreciate your prompt response.

I will try it.

What kind of noise pattern should I input with a noise generator?

If there is reference, please tell me any information.

Regard.

Hiroshi Nakata

[Hui_Ma · Accepted solution]

Hi,

For the UART is over sampling and in general it will using a frequency 16 times of the baud rate as over sampling frequency.

For example, if UART baud rate is 115200, customer need provide a 1.8432MHz (115200 X 16 ) square wave as the noise source.

During the UART communication, customer can connect 1.8432MHz square wave signal to UART RX pin.

Wish it helps.

Have a great day,
Ma Hui

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Note: If this post answers your question, please click the Correct Answer button. Thank you!
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[hiroshinakata]

Hi

Thank you very much for your response.

I'll try it reference your information!

Regard.

Hiroshi Nakata