Trying to figure out why my timer only ticks once
You need to provide more context. By "timer" are you refering to one of the hardware timers or something like a software timer for a RTC that "ticks" periodically? Speaking from experience, if it's a hardware timer, it has to have a clock source. If that source is not internal, then maybe your external source is not connected or not working. If it's something that gets an interrupt each time, then maybe the interrupts were not cleared to reenable them. Same goes for software timers, which are usually triggered by a hardware timer (e.g. to "tick" every X msec): if the hardware timer was not set correctly, then that could be the problem. Or if it's OK, then the interrupt for the "tick" was not cleared for the next tick event. If's always better to provide more details, then not enough. It's like aliasing when sampling analog signals for DSP, if you sample slower than the Nyquist rate, you most likely will not get what you wanted (unless you intentionally undersampled because it then aliases into a clean part of the spectrum), but I am providing too much detail.