I have programmed my ESP32 to (supposedly) output a megahertz-range clock signal, to use as a substitute for a broken clock crystal on another microcontroller. The code I used is adapted from this esp32 forums post.

However, it appears that the target microcontroller is not responding to the clock signal. To at least make sure it's getting a signal at all (and the problem is with the target microcontroller, not the esp32), I want to detect that the esp32 is outputting the signal out of the intended pin.

I do not have access to an oscilloscope. How do I do this?

I have programmed my ESP32 to (supposedly) output a 12 MHz clock signal, to use as a substitute for a broken clock crystal on another microcontroller. The code I used is adapted from this esp32 forums post.

However, it appears that the target microcontroller is not responding to the clock signal. To at least make sure it's getting a signal at all (and the problem is with the target microcontroller, not the esp32), I want to detect that the esp32 is outputting the signal out of the intended pin.

I do not have access to an oscilloscope. How do I do this?

EDIT: I also do not have access to a frequency counter, logic analyzer, etc. And the target uC must be run at 12MHz or it will not work (it has internal DRAM, not SRAM).

Also, the esp32 is outputting the signal using the "ledc" peripheral, which is basically a PWM counter. It is not bit banged in any way.