8.5.1.4 SPI Data Output (SDO):

This pin is high impedance until the SPI output is enabled via nCS. Once the SPI is enabled by a low on nCS, the SDO is immediately driven high or low showing the Global Fault Flag status which is also the first bit (bit 32) to be shifted out if the SPI is clocked. Once SCLK begins, on the first low to high edge of the clock the SDO retains the Global Fault Flag which is bit 31 of the shift. On the first falling edge of SCLK, the shifting out of the data continues with each falling edge on SCLK until all 32 bits have been shifted out the shift register.