NXP 4300 SGPIO slew rate of SGPIO pins for pull down is slow

[marvincabuenas]

Hello,

I am having some problems with regards to the slew rate of SGPIO pins for LPC43xx. For SGPIO pins with external clock source based on the output of a SGPIO pin, we see that the falling edges of the output of the SGPIO pins is very slow. Please see screenshot attached. The yellow waveform is the output of an SGPIO pin that is used as an input clock source for the blue waveform. Do you have any recommendation on what to do with this issue?

[xiangjun_rong]

Hi,

Regarding your question, it appears that the red waveform is neither push-pull output nor open-drain output, after the falling edge of red signal, the pin is float or tri-state.

I do not know why. As a workaround, pls try to connect an external 5K pull-down resistor, what is the result?

BTW, what is the logic you have implemented?

Hope it can help you

BR

XiangJun Rong