I've build a 1-wire network using a star topology (networking done trough my home's ethernet cables).
At the begining I didn't own a 4.7k resistor but some 1.2k resistor so I lined them to achieve 1.2k*3= 3.6k "virtual resistor".
This first version of my bus was working fine.
Today I tried to replace those 3 resistor by a single 4.7k and the bus stopped working.
==> Why ? :)
[EDIT] second question added below
Following maxim's guide I think I understand that, with a star topology, one should rather use a switched network or a Distributed Impedance Matching.
I'm more keen to try this second option but how can I compute the optimal resistor to add to each branch given their length ?
Star topology metrics are : 4 branches diverging at the master
- 1st branch = 18.5m
- 2nd branch = 26.5m
- 3rd branch = 25m
- 4th branch = "1cm" (direct connection to my 3.6k resistor)
Thus the radius of the longest branch is ~27m and the radius of the shortest is 0cm and the total weigth is 71m