Controlling CAN terminator with Propeller pin.

sccoupe

I'd like to be able to switch the terminator resistor on and off with a propeller CAN node programmatically instead of using using a physical jumper. I thought of using a tri-state buffer, but the bus voltage goes over the usual 5v allowed. Most of the transistor examples are switching voltage a don't seem valid for the changing voltages of a CAN bus. A physical relay also isn't preferred. There is a way, I just have found the right search terms...

AwesomeCronk

So, what exactly are you controlling?

sccoupe

Terminating resistor enabled or disabled.

Phil Pilgrim (PhiPi)

Use a FET-output optocoupler, such as the TLP3545A, with pins 4 and 6 (in this case) in series with the resistor.

-Phil

Mark_T

Or an LDR output opto coupler (though some experimentation needed for the right resistance value) for instance NSL-32SR2

jmg

sccoupe wrote: »

I'd like to be able to switch the terminator resistor on and off with a propeller CAN node programmatically instead of using using a physical jumper. I thought of using a tri-state buffer, but the bus voltage goes over the usual 5v allowed. Most of the transistor examples are switching voltage a don't seem valid for the changing voltages of a CAN bus. A physical relay also isn't preferred. There is a way, I just have found the right search terms...

As above, if you want the full transient tolerance of CAN, some isolation is needed.
Phil quotes a 4A SSR, but you might be ok with smaller/cheaper ones. egg CPC1006N, VO1400AEFTR , CPC1002N, TLP241A(TP1,F etc

Peter Jakacki

I've used G3VM-61G1 optos for electronic termination selection. They are 1ohm 400ma devices but listed as EOL which is not a problem but the replacement is G3VM-61VY