I am working with the HMC832LP6GE Evaluation Kit. I can get the PLL to program and output a frequency with the USB interface kit and PLL Eval Software. However, I have not been able to program it in our circuit. I hooked a logic analyzer up to the eval kit and discovered that the SPI Protocol does not match the timing diagram in the Datasheet. http://www.analog.com/media/en/technical-documentation/data-sheets/HMC832.pdf Page 30.
1. I found that the SEN pin is inverted. The signal on the evaluation kit is behaving as an enable high instead of an enable low. The diagram is a little confusing. It switches half way through the write. My team and I are interpreting the SEN signal in this diagram as an enable low.
2. The data structure seems to be incorrect.
The structure I found is:
Ax Ax, R4 R3 …. R0, D23 D22 …. D0, Ax
Where the datasheet calls the following structure:
D23 D22 …. D0, R4 R3 …. R0, Ax Ax Ax
A is the chip address. Always zeros
R is the Register address (R4 is MSB)
D is the Data (D23 is MSB)
I have attached a screenshot of a logic analyzer recording a write to enable RF_P. This was recorded using the Eval software by clicking the Enable RF_P check box. Using the structure I found this decodes to the following:
Chip Address = 0x0
Register Address = 0x5
VCO Register Address = 0x3 D[3:0]
VCO Data = 0x19 D[23:4] (Default || enable RF_P)
Would someone please clarify the discrepancy between the datasheet and my measurements for me? We have not yet been able to program this chip with a micro-controller so I believe we are still missing something.