Thank you all for your contributions which I will go through and will make every effort to understand and get this to work. Despite what aarg says, I wouldn’t be here if I had found even one example that showed breakTime in action
It is hard for anyone without formal training to get their heads around the precise workings of one language, let alone two.
I like to make things work and try never to give up - my whole working career has been about solving problems in an industry that is fundamental to public health and I would get involved when the day-to-day operators had hit the buffers with a problem. I quite often threw solutions at it until one stuck which gave you breathing space, then remove them one by one at leisure until you find out the root cause.
There are contributors on the forum who eat and sleep code and have scant regard for those who aren't so fluent and belittle their efforts - with the right reasons at heart. Everyone starts somewhere and the Arduino user community covers the whole range of abilities. Others with huge knowledge on the subject freely make their knowledge available to all. Not a lot of point in taking a lifetime's knowledge to the MCU in the sky. I know what's behind quotes like "get your wallet out", but it's all about open source.
I use cut and paste a lot and rely heavily on tutorials and examples - I don't need or want to spend hours in what is already a busy day learning every full stop to get an LED to flash. I can't remember where I first heard about Arduino, but it opened up a whole new interest.
Right now I'm working on an MSF clock project, but rather than just buy the ferrites and a decoder, I'm winding my own coils and putting RF amplifiers together - I'm going through a completely new subject, namely radio reception and already it has been satisfying just to get a resonant circuit plumb on 60-kHz. Never heard of Litz wire before. Even dug the old crystal set out. My eureka moment was as a child discovering that connecting a torch lamp to an EveryReady battery with a couple of bits of fuse wire made light.
Arduino Cookbook is my bedtime reading, with others, but write the book, not in an epoch.
I'll let you know how I get on, and thanks again.