As the Siggaph task is finished and the finial version of display menu haven't come out. I start to design the entire system circuit.
The fisrt thing we need to design for the system circuit is the power circuit. the requirement of power circuit is as follow:
  1. Support both DC and USB charging for Li+ ion battery.
  2. Can give both 5V and 3.3V power supply for different components.
By searching the  IC in the database of Farnell, Digikey, and RSsingapore, we use MCP73318 as the charger IC which is small in size and cheap in price. More importantly, it can fulfil the functional requirement.
For the power supply IC, we use a buck booster TPS6330 which can boost the Lio+ ion battery from the 2-5V to 5V.  In addition, we use a normal voltage regulator TC1108-33 to regulate the 5V output to 3.3V.
As I discussed with Isuru, we put the component on two boards, master board and slave board. The master board will put the master PIC, Bluetooth and  USB port on it. and the slave board will put the slave PIC and power circuit on it.
The schematics of the two board have been finished and already sent to Japan side for evaluation.