DSP Controller Requirements

[diaverik]

I have a K40 as it came. I want to upgrade using the 2012 DSP controller, but I don't wanna buy the full kit. What are the minimum required add-ons I need for the DSP controller to work?
My list so far include the following:

1 2012 DSP CONTROLLER
2 Mini 2 Phase 1.5A 1-axis Stepping Motor Driver
1 DC 24V 5A Switching Power Supply

Can someone explain WHY or IF i need the new switching power supply? And what else might I need?