easier-to-understand way to go back to default refclk settings

[kevinkiener]

When reloading the QickSoC with an external_clk=False the setting did not change because the if condition was not fulfilled. Now it checks whether the clocks have previously been set to an external_clk or not.

[meeg]

As things stand, if there's a possibility that the clock settings have been changed you need to set force_init_clks = True to reload the default settings. Certainly this is not ideal.

This fix doesn't work in all cases - it works if the libraries remain loaded and you're just reloading the QickSoc, but it doesn't work if you're reloading the library as well (restarting your notebook/script, or working in a different notebook). In that case the xrfclk library will have been reloaded, and the check will always set clock_initialized = False.

Given that there is no obvious way to make the software always do the right thing, I would prefer to leave things as they are (you don't need force_init_clks = True to change the clock settings, but you always need force_init_clks = True to restore normal settings) or go back to how things were when you submitted #99 (you always need force_init_clks = True to change or restore). It seems more confusing to add this PR (you sometimes need force_init_clks = True to restore normal settings).

Thoughts?

[meeg]

Another possible tweak is to make it so specifying any value (either True or False) for external_clk triggers a forced reload. Would that work for you?

[kevinkiener]

Yes, that's a good idea, so I can change it to have a default value of None and then if the user sets it to true or false we will reset the clocks/ force reload