Why is my DAC not working?

I'm trying to program an AD5754 DAC from Analog Devices. As far as I can tell, it's connected properly and the signals I'm sending to it are perfect. Why am I getting no response of any kind?

Green is Slave Select (SS/Sync), purple is Clock (SCLK), yellow is MOSI, blue is MISO. I'm trying a basic write/read test. It's a 16-bit DAC, so each command/word is 24-bits (3 bytes) long. One-byte register, 16-bit value.

I send the first word, saying "tell me your voltage range", then wait for a response.

The blue line shows the response. No response. I'm doing everything right. Seriously. Latch, start the clock, store data on the falling slope of the clock, unlatch ...

... just like this picture says I'm supposed to. I'm meeting all the time requirements.

And yet, no activity of any kind. What's going on?

Update (2015-04-15)
The chip was dead. I don't know how or why, but it was. I replaced it and now it's working fine. Ugh.