Retaining a PWM signal setup in bootloader


New Member
Jul 30, 2020
Reaction score
Hello and thanks for taking the time to read this thread,

I have a proprietary bootloader (for which I have the sources) that I have slightly modified to generate a PWM signal. This has to be done as early as possible; using a script launched via "etc/init.d/rcS" is not acceptable, unfortunately.
Now, I need to maintain that signal until the application takes over and changes the frequency, but what I see happening is that as the kernel is booting, the PWM signal is disabled due to the entry in the device tree which describes it, probably due to the kernel reconfiguring the peripheral.
I have noticed that removing the "offending" PWM entry from the device tree will indeed allow the signal to be employed as the kernel starts up, but then of course the kernel's "/sys/class/..." folder structure will not be available for that PWM output which is not acceptable.
My question is: Is there a way to maintain the PWM signal setup in boot while preventing the kernel from resetting it until the application is started?

Thanks in advance!

Members online

Latest posts