Title itself is explanatory. Also tell me what are the things I should take care of when I connect other IC's to it? With AVR's I never had to deal with these things. But now when dealing with ARM MCU's I think I have to consider these stuffs.
I will rephrase the question. Tell me, is it safe to connect LPC MCU to other common IC's like an AVR or L293D diver IC or 74xx series IC's etc without any interfacing circuits?
Best Answer
The LPC1xxx family has 3.3V IO but it is 5V tolerant. This means that it will only give 3.3V when you output '1' but it will tolerate up to 5V when the pin is configured as an input. Many other 3.3V MCUs/logic chips are not so convenient.
What this means in practice is that you can connect to almost any standard 5V logic chip. You lose a a bit of noise resistance but I never found this to be a problem.
The thing to remember is that you will need two supplies: one 3.3V for the LPC1xxx and another 5V one if you wish to use some 5V chips. You cannot run the LPC1xxx from 5V! (but you can use just a simple low drop-out regulator to get from 5V you have to 3.3V you need)