HMC1044 SPI configuration

Apologies as there is some confusion between the total bits clocked in and the length of the data bits. 

Yes, each SPI transaction is 16 bits long, 9 of which are data, 4 are register address and 3 are Chip address.

The data bits only take up the four LSBs of the 9-bit data word, so to write to the autotune register, you would write:

0b[0 0 0 0 0 d3 d2 d1 d0 0 0 0 1 1 1 0]

where d0, d1, d2 and d3 are the four relevant data bits whose value ranges from 0b0000 to 0b1111

Hope this helps!

Now it's clear, thanks.

Stéphane