configuration register 1
| DSIZE | Number of bits in at single SPI data frame  |  
| FTHVL | threshold level  |  
| UDRCFG | Behavior of slave transmitter at underrun condition  |  
| UDRDET | Detection of underrun condition at slave transmitter  |  
| RXDMAEN | Rx DMA stream enable  |  
| TXDMAEN | Tx DMA stream enable  |  
| CRCSIZE | Length of CRC frame to be transacted and compared  |  
| CRCEN | Hardware CRC computation enable  |  
| MBR | Master baud rate  |