SPI0 misc register
SPI_MEM_FSUB_PIN | For SPI0, flash is connected to SUBPINs. |
SPI_MEM_SSUB_PIN | For SPI0, sram is connected to SUBPINs. |
SPI_MEM_CK_IDLE_EDGE | 1: SPI_CLK line is high when idle 0: spi clk line is low when idle |
SPI_MEM_CS_KEEP_ACTIVE | SPI_CS line keep low when the bit is set. |