Can I invert the output of OSPi in software ? Driving active low logic

[Dale March]

Hello all,

I am using the normal shift register logic to drive a relay board, but the relays are all on when the interface shows all circuits off.

I could add inversion logic, but it seems that it should be an easier fix in software. I am not quite familiar enough with Python (yet) to know where to look?

I can post my relay interface if anyone is interested.

[Ray]

Some relay boards are ‘active high’ and some are ‘active low’. The default logic of OSPi is ‘active high’, so you will need to use relays boards that are ‘active high’.

To reverse the logic in software, go to the ‘apply_all_station_bits’ function, and simply reserve the bits that are being pushed to the shift register.

[Dale March]

I forgot to include that I am using the OSPi software from Dan-in-Ca version 2.2.35. I cannot find the suggested apply_all_station_bits function so I suspect that is the interval version, or I just don’t know where to look.

Dale

[Dale March]

OK, Thanks for the hints. I found it in gpio_pins.py in the setShiftRegister(srvals) definition.

Seems to be working like a charm!

Dale

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