Ground and Vcc

RogerInHawaii

I have a chip that I'm currently controlling from the Propeller chip. The input pin on this chip expects to be connected either to ground or Vcc. When it's connected to Vcc the chip behaves in a certain way, and when it's connected to ground it basically turns off that behavior. I'm controlling it with one of the pins, configured for output, on the Propeller. All well and good, it works just the way I want it to because, a 1 written to the Propeller's output pin makes it Vcc and a zero written to the pin makes it connected to ground, right?.

But I now need that chip (let's call it Chip A) to be controlled, not by the Propeller chip, but by yet another chip, which I'll call Chip B. The output pin on Chip B varies between zero volts and Vcc. I want to use that Chip B output pin to control Chip A via its input pin, which expects either Vcc or ground. Will this work? In particular, will a zero voltage value from Chip B be equivalent to ground, as expected by Chip A?

Phil Pilgrim (PhiPi)

If the output of chip B is zero volts, that's equivalent to a logic "low", and chip A should interpret it that way. Likewise for an output of Vdd, which will definitely be interpreted as a "high". Much dicier are those values between zero and Vdd. It's rather unusual (but not unheard of) to drive a digital input with an analog output. Can you divulge what it is you're doing? More complete answers might then be available.

-Phil

StefanL38

as long as all grounds are connected together this should work. For reliable function the important thing is that your input-pins has 0V or Vcc
REFERENCED upon the ground of the same CHIP. If you connect all grounds they all have the same reference

best regards

Stefan