I am using some parts to build up a transmitter module. Among the parts are the ADuC812, the ADF4350 as well as a bi phase modulator. I need two SPI interfaces to write to the ADF4350 registers and to transmit my binary Manchester data to the modulator. For these two, I would need the ADuC812 to operate in the master mode. Can any one suggest how to go about this? Do I have to use two uConverter parts or can one suffice for me?