Thanks much @Gordon for that relative path. Now for the 'Friday Funnies!' We'll all get a good laugh at my expense. . . .
Lack of familiarity with VSCode caused me to have blinders on when using the hyperlink to both function definitions and declarations. I couldn't get passed why there was no corresponding .c file anywhere in each of the visible views. While using the file explorer within Windows10 was time consuming, and experience has taught me that if an internal System Service hasn't completed indexing, it is quite possible that the desired file is never (reasonable time frame) found. So I went to Google to search GitHub. None there either. So, I falsely determined that the content I was after was somehow pre-compiled into one of the .bin files used to flash Espruino, having no other explanation. Using the relative path that you provided, I searched GitHub again, and this time a result. So, curiosity forced me to find the reason why a search yesterday didn't locate that file.
Drum Roll Please . . . . . the funny part . . . .
I went through Chrome History to locate the search string. Couldn't believe my eyes! While I had used the wildcard '*' to perform the recusive file search using File Explorer yesterday, when I jumped to using the Browser, I had only searched for 'hardware.c' without the wild card as not permitted, at GitHub. Looks legit when typed, but somehow never registered the omission. okay, . . . . stop laughing . . . please!! ;-b)
Lesson here: Enjoy your youth and quick thinking mind while you have it - I'll get the last laugh on the other side
Back to the project:
'The RTC only runs at 32kHz so you may find it's not accurate enough for you'
'One of the Timers might be better'
The issue I had here was that I couldn't get a narrow enough pulse, and a train of pulses in a narrow enough time interval. Back then, I shelved the project at that point, but would need to put some time in to determine the limitations.
'Some of the hardware is used by Bluetooth and we have only limited control/usage of it'
Thanks for that tid-bit. I may resort back to the WiFi, also having the extra memory benefit.