1.This installer contains Atmel Studio 6.1 update
2.with Atmel Software Framework 3.11.0 and Atmel Toolchain. Update from Atmel Studio 6.1 update 1 to get support for SAMD20 with JTAGICE
3.This installer also contains MS Visual Studio Shell and .NET 4.0. Select this installer if you need to install Atmel Studio on a computer not connected to the internet.