SPI1 misc register
| CS0_DIS | SPI_CS0 pin enable, 1: disable SPI_CS0, 0: SPI_CS0 pin is active to select SPI device, such as flash, external RAM and so on. |
| CS1_DIS | SPI_CS1 pin enable, 1: disable SPI_CS1, 0: SPI_CS1 pin is active to select SPI device, such as flash, external RAM and so on. |
| CK_IDLE_EDGE | 1: spi clk line is high when idle 0: spi clk line is low when idle |
| CS_KEEP_ACTIVE | spi cs line keep low when the bit is set. |