I bought one of those recently and I was surprised by how inaccurate it was. It drifted like 15 seconds every month. From what I've been reading, that is normal, but I was surprised - with all the technological advances that we have it is odd to think that cheap timekeeping is not a solved problem yet!
Also: how is the software of these watches without a CPU designed? Is it something like Verilog or whatever?
Also: how is the software of these watches without a CPU designed? Is it something like Verilog or whatever?