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Red face is there sth. wrong with LPC1114



I had burn several LPC1114 in the circuit below.After I use it for hours, the PWM signal produce by LPC1114 became square wave limited between 3.3V and 2.5V. Is it possible that the LPC1114 is too unstable.Or the value of the resistor is not proper,or the may be sth. wrong with other parts of my circuit?

What should I do when I want to sample a 5V sensor using a 3.3V MCU

I want to get the output of SCA60C using the ADC of LPC1114.SCA60C is a 5V chip while LPC1114 is a 3.3V MCU. what should I do to put them together?

RPR220 detect black line, problems with distance

I want to detect the black line with RPR220 when building a line tracker. I connect the rpr220 output to a LM311 the comparator.but when it can detect the black line when the distance between RPR220 and the line is 2.5cm,it cannot do it correctly with the distance 1.5cm. And recognize the black line as the white background .

the voltage on the collector of RPR220 can clearly distinguish black and white at a certain distance, but cannot do it if the distance is closer ,why is that?