kStatus_UART_NoiseError is set on line with about 340mV of noise

[stdcerr]

Hi,

I'm attempting to receive data from UART4 on our custom board but UART_ReadBlocking returns kStatus_UART_NoiseError even though there's minimal error on the actual MCU's Rx pin.

The UART in question is receiving data from a RFID reader at 9600bps while I also have a debug UART setup at 115200 bps. They are both configured with the same clock frequency and hence I think that my clocking should be okay. More particular, I pass "CLOCK_GetCoreSysClkFreq()" as uint32_t srcClock_Hz to UART_Init().

Since the noise on the line doesn't seem to cause havoc either, what else might be causing this issue?

[stdcerr · Accepted solution]

If you get here with the same or a similar problem, check your clock source setup, turns out I didn't initialize the UARTs with the correct clock sources myself. I had to use UART4_CLK_SRC to feed into CLOCK_GetFreq() to get the correct frequency for the different UART modules.