ADIS16448 Writing to Registers (example DIN = B504 for self-test enable)

Hello! I hope you can help me out with my confusion. I am wondering as to how is the command 0xB504 formed for the activation of the self-test function? From the timing diagram, DIN has the format:

[15] - !Read/Write
[14:8] - Address
[7:0] - DC

I'm trying to create a function for writing to the registers of ADIS16448 and if I was to follow the format from here and use the MSC_CTRL as an example my data would be:

[15] - !Read/Write - 1
[14:8] - Address - 011 0100 or 0x34
[7:0] - DC - ?
my first 8 bits would be 10110100 or 0xB4, I'm having trouble as to what my DC or bits 7 to 0 would be and how the final command for the self-test is equivalent to 0xB504?

Thank you for your help!