I am sorry for not explaning my problem properly.
This is my project.
I have 1 DSP board F2812, 1 LCD, 1 Signal conditioning and I/O board.
Opamp in I/O board generate output in range -9/+9 which goes into AVR to control generator voltage. Generally it never goes into that range but it MUST suppport output between -9 to +9.
Right now I am using different power supply for each , but I need to design one power supply for all of three (+12,-12,+5,+3.3)
and input to this supply will be +12V battery.