Content originally posted in LPCWare by PhilYoung on Tue Jun 19 14:33:03 MST 2012
decoupling depends on the PCB design also, so is not a simple answer.
Clocking is simple as the device has an internal RC oscillator that it uses at startup so you can choose almost anything, the PLL is very flexible so you only need to ensure you meet the frequency stability requirements for USB.
Pins for an interface is not a simple answer either as most interfaces have multiple pin selection options, the device is VERY flexible in this respect. The starting point is make a list of what signals you need, each section in the UM usually defines what is the minimum requirement, then use a spreadsheet so allocate these to available pins. Start with the EMC since these pins have the fewest options in terms of multiplexing. It's a tedious process.
The device seems to consume < 200mA with most functions operating, and has an internal regulator which helps, I've not seen any issues with power supply design for it just using a variety of different LDO's, it always seems to boot correctly so that does not seem critical.