L9825 SPI Control Not Functioning

[MBoren]

I am attempting to set the output states of an L9825 using its SPI interface, but no matter what byte is transmitted, the returned diagnostic byte is 0x88 and the output state is unaltered.

• clock frequency : 1 MHz
• clock polarity: low
• clock phase: data changes on rising edge
• transmit order: MSB first
• NON1/2 pins are held high
• nRes is held high
• Vcc: 3.3V

What am I missing?