I have designed a custom board with adf5901. After power up of the board, I enable the chip by supplying 2.5V to CE pin. Then I try to write register R3 to program the MUXOUT to give 3.3V (high). But looks like the chip is not responding at all. The MUXOUT is stuck at 0.6V and there is no difference in any of the pin voltages. I cross checked the SPI timing using scope and it all looks fine to me. I got the chip replaced thinking it was damaged, but then nothing was fixed and I still see the same. I bought the radar mmic2 eval board to cross check the pin voltages one on one. I didnt see any major problem. Also compared the SPI transaction on scope to see no difference between eval board and my board. Is there something that I am missing? I want to know if the sequence of register write is correct.
1. I power up the board and set chip_enable = 1.
2. Then I write the register R3 with 'h01891803 only once. (No double buffering)
Is this sufficient to set the MUXOUT pin to 3.3V?
Also, can I find the log of eval board GUI somewhere? Maybe I can trace the SPI writes performed by click of each button in the GUI so that I can replicate that in my software. That will be very helpful.