Electronics > Beginners
Digital Communication Via VCC and GND
NickyYTSRB:
How can I establish digital communication between microcontrollers like powerline but on smaller voltage, for example: I have 2 wires that will caryy 24VDC as supply voltage and data. On transmitting side data has to be injected into 24VDC line and on receiving side data has to be extracted and that same 24VDC must power the ic which has to read that data. My goal is to establish communication between 3.3V or 5V mcu with one wire protocol(One way UART for example).
I found this on internet:
Is this enough or i have to add more stuff to this circuit. My goal is UART at 112.5kbit.
Paul Rose:
The idea is sound, you may need to play with component values.
Figure the lowest/highest frequency component of you signal and compute the inductive and capacative reactances of your L and C components.
You want a larger inductor ( higher XL ) and larger capacitor ( lower XC ) for lower frequency signals.
You want to pay attention to the DC resistance and current handling of you inductors to make sure you can supply the power for the DC load.
Look up "bias tee" for ideas, but these are ususally for higher frequency signals ( RF ).
Paul Rose:
You also might need to do something to re-establish DC level on the receive side signal output. The signal will appear to vary about 0v, which might not be what your UART expects.
HB9EVI:
EIA232 is not DC free, so that's not going to work.
If you want to stay in the baseband, you need at least a DC free coding; much better would be a modulated transmission
Paul Rose:
--- Quote from: HB9EVI on September 18, 2018, 03:54:50 pm ---EIA232 is not DC free, so that's not going to work.
--- End quote ---
Of course :palm:
Sorry about that.
The "lowest frequency" component of 232 is esentially DC, which you can't separate from your power.
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