I've been using NXP LPC microcontrollers for some time. One problem that I've faced in several projects is that every time the MCU is powered and a GPIO is setup to LOW logic level and output, a glitch in the GPIO pin happens.
Even considering that this glitch has low amplitude and is fast, anything connected to the GPIO can have undesired behavior on board power up.
Some time ago didn't know about this behavior I connected the GPIO to a MOSFET gate that was controlling a TRIAC (for AC motor control). Because of this glitch problem, everytime the system was turned on, the motor quickly bumped/shaked. In this particular problem I had to change the MOSFET from N channel to P channel and invert the GPIO logic so it won't glitch anymore. Problem fixed.
Anyway, I'm having this problem again in a project that I cannot keep changing or adding components to the board (for space and costs constraints).
Does anyone knows how can I eliminate this glitch?