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spike on a GPIO pin on power ON

Question asked by yafis.mohamed on Nov 11, 2015
Latest reply on Nov 12, 2015 by yafis.mohamed
Hi STM32 forum.
I am working on a custom board with STM32F030 controller on it. In my setup the GPIOs are connected to triac ICs which drive the external load(bulbs). The GPIOs init is as given below:
     GPIO_InitTypeDef GPIO_InitStructure;
     GPIO_InitStructure.GPIO_Pin      =      GPIO_Pin_3;
     GPIO_InitStructure.GPIO_Mode      =      GPIO_Mode_OUT;     
     GPIO_InitStructure.GPIO_OType     =          GPIO_OType_PP;
     GPIO_InitStructure.GPIO_PuPd      =      GPIO_PuPd_UP ;
     GPIO_InitStructure.GPIO_Speed =      GPIO_Speed_Level_1;
     GPIO_Init(GPIOB, &GPIO_InitStructure);

I am observing an initial spike(on scope) of about 1.5ms on power ON, on the GPIO pin that is connected to one of the triac due to which there is a flicker in the load(bulb). I am not sure what is creating the problem. Any help/suggestions will be very helpful.