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LPC546xx uart RxNoise

Question asked by de_sach on Oct 8, 2019
Latest reply on Oct 16, 2019 by de_sach

Hi,

 

I have been struggling with a RxNoiseInt when using UART on a LPC54607.

I use the FLEXCOMM2 peripheral with a clock from the kFRO12M.

At a certain point in my communication (can be 5 messages, can be 10000+ messages), a rxnoiseint is generated.

 

However when I measure the signal with the scope I see less than 1% offset in baud rate.

When calculating the clock the baudrate is 19.2kHz ((12 MHz / oversample rate) / BRG divide = (12Mhz / 16) / (38+1) = 19231 Hz

So when oversampling 16 times I don't expect a noise error when the baudrate is 19231Hz.

 

The device I'm communicating with receives the messages I sent and answers on the messages without an error.

 

At the point I receive the noise interupt i disable the peripheral and reïnitialize it. The config registers of the USART2 peripheral are initialized to the same values after the reset. At this point it can send a message which is received correctly in the target. However when the LPC54607 receives a message the peripheral keeps setting the rxnoiseint flag.

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