LM51551-Q1: about the

Tool/software:

hello

i have one question about the LM51551,I applied this chip to perform sepic topology control

Is there any problem with me controlling the UVLO pin of the chip through 5V LDO and MCU I/O?

I found that there is a step waveform in the voltage of the UVLO pin,I don't understand why there is a step waveform,

can you help explain it？