SPI clock Divider
| DIVVAL | Rate divider value. Specifies how the PCLK for the SPI is divided to produce the SPI clock rate in master mode. DIVVAL is -1 encoded such that the value 0 results in PCLK/1, the value 1 results in PCLK/2, up to the maximum possible divide value of 0xFFFF, which results in PCLK/65536. |
| RESERVED | Reserved. Read value is undefined, only zero should be written. |