I have Worked on few development boards of arduino such as nano,uno,mega,etc. But how can we design our own microcontroller board? what is the procedure to design them and which softwares are used?
waiting for an appropriate answer. Thanks in Advance.
I'm all for electronics, so please don't let my next comment put you off, but I agree with clem57 comment - is it worth it? There are so many great dev boards avaiable at very reasonable cost.
What would be the goals of designing your own? A few answers could perhaps be:
Out of interest shakti334 who are you referring to by the following statement - a buisiness company, a maker group, some friends or a school/university group ?
But how can we design...
If you did want to take this route it very much depends what skills you have and which are available. Personally if making myself I would use the tools and manufacturers I was most familiar with.
Therefore I would already know that my board would utilise one of the Microchip MCU devices as I am experienced in using those. I would think about what specification I needed on the board and identify some suitable device familes. I would look more closely at the footprints and costs if it were for mass production and eventually select a model to use. I'd do lots of reading of the datasheets. I'd identify other circuit components required such as a buffer, USB-UART bridge, power supply, programming header, and whatever else my specification needed. I would identify the actual components required and then start making the PCB design. For that I would use Autodesk EAGLE because I am also familiar with that. Others would likely use Altium Designer or one of the other PCB packages. To have the 'Arduino experience' of a managed boot up you would also need to start writing some boot code (which would also setup and run the UART/USB). You'd likely need a few test boards to rigorously check for operation.
If you were marketing this you would have lots of other things to do. For example local regulations to comply with - RF interference, component specifcations, electrical safety. You would need documentation, a website ready for startup and tutorials. You would need packaging, branding,advertising and customer support.....lots to do and it nedds doing those parts well to make it successful. Finally after all that effort you would find things are moving on and so this would need to be a quick process and one you find you have to repeat quite often. If that is still your aim then I wish you well 
I'm all for electronics, so please don't let my next comment put you off, but I agree with clem57 comment - is it worth it? There are so many great dev boards avaiable at very reasonable cost.
What would be the goals of designing your own? A few answers could perhaps be:
Out of interest shakti334 who are you referring to by the following statement - a buisiness company, a maker group, some friends or a school/university group ?
But how can we design...
If you did want to take this route it very much depends what skills you have and which are available. Personally if making myself I would use the tools and manufacturers I was most familiar with.
Therefore I would already know that my board would utilise one of the Microchip MCU devices as I am experienced in using those. I would think about what specification I needed on the board and identify some suitable device familes. I would look more closely at the footprints and costs if it were for mass production and eventually select a model to use. I'd do lots of reading of the datasheets. I'd identify other circuit components required such as a buffer, USB-UART bridge, power supply, programming header, and whatever else my specification needed. I would identify the actual components required and then start making the PCB design. For that I would use Autodesk EAGLE because I am also familiar with that. Others would likely use Altium Designer or one of the other PCB packages. To have the 'Arduino experience' of a managed boot up you would also need to start writing some boot code (which would also setup and run the UART/USB). You'd likely need a few test boards to rigorously check for operation.
If you were marketing this you would have lots of other things to do. For example local regulations to comply with - RF interference, component specifcations, electrical safety. You would need documentation, a website ready for startup and tutorials. You would need packaging, branding,advertising and customer support.....lots to do and it nedds doing those parts well to make it successful. Finally after all that effort you would find things are moving on and so this would need to be a quick process and one you find you have to repeat quite often. If that is still your aim then I wish you well
