The BF707 will used as a host. It will send data, when SPI_RDY pin is low. The BF609 will used as a SPI slave. The SPI_RDY pin must have 10K pull up resistor. The connection are given as below.
BF707 SPI Host BF609 SPI slave
SPI2_CLK (P1B 107) SPI1_CLK(P1B_82)
SPI2_MOSI(P1B 108) SPI1_MOSI(P1B_84)
SPI2_SSEl1(P1B 110) SPI1_SSEL1(P1B_39)
SPI2_RDY(P1B 48) SPI1_RDY(P1B_50)
The SPI MUX and FER register configured using addin plug in system.svc.