I am using an X310 with a custom daughterboard. The daughterboard is expecting the X310 to use the 120 MHz clock speed. The daughterboard is hardware defined to accept a 120 MHz signal to create an internal 60 MHz clock. The daughterboard upconverts a low IF signal to 60 MHz. The X310 is setup with a center frequency of 60 MHz and a sample rate of 4 MHz.

I have upgraded from GR 3.7 to GR 3.10 and upgraded the firmware as well. The daughterboard was working on 3.7. On 3.10, we can no longer set the master clock rate to 120 MHz and the daughterboard is no longer working as expected.

We tried using the 200 MHz master clock rate with the daughterboard clock rate of 60 and 100 MHz. We set the sample rate to 4 MHz. If we set the daughterboard to 60 MHz with the input tone of 500 kHz, we see nothing. If we input a 61 MHz tone, we see a 1 MHz tone. This is telling us the mixer signal is not working properly. If we set the daughterboard clock speed to 100 MHz, we see the same results. Based on this, we cannot use software to change the daughterboard clock rate.

We tried setting the master clock rate to 120 MHz and got a run time error. The runtime error is as follows:

RuntimeError: ValueError: Invalid device args value: master_clock_rate = 120000000.000000 (Minimum: 184320000.000000, Maximum: 200000000.000000)

We looked at the docs to set the clock rate back to 120 MHz and found no results. We saw on the general overview that other clock rates were available, but the detailed docs only shows integer decimation. It does not show how to get other clock rates.

Is there a way to use up to date firmware to set the master clock speed to 120 MHz? If not, how can we roll back to a previous firmware version that can interact with GR 3.10 and the associated UHD version?