I am trying to use this multiplexer with a raspberry pi and am having difficulty getting it to work.

here is the datasheet: https://datasheets.maximintegrated.com/en/ds/MAX378-MAX379.pdf

I think my problem lies with the pin configuration, specifically V+ and V- as shown here: enter image description here

to test this I have the mux on a breadboard and have an LED connected to IN1 and +5v coming from the pi

The datasheet shows that the recommended power supply is 15v so I have a 15v dc transformer connected to V+. The negative from the transformer is connected to the "-" rail on the breadboard. V- on the mux is connected to the "-" rail on the breadboard (I've also tried just using the 5v power source and ground from the pi to no avail)

I don't have anything connected to A0, A1, A2 since the truth table on the datasheet shows that IN1 will be switched on if they are 0 and EN is 1

I have the OUT pin on the mux connected to ground from the pi

The expected result is that the LED will light up when EN gets voltage from a GPIO on the pi. I've confirmed that the gpio pin I'm using does go high when I trigger it in a python console but when I connect it to EN, IN1 and OUT don't appear to be connecting as I would expect.

I'm a total newb when it comes to this stuff so I'm hoping what I'm doing wrong is fairly obvious and someone can help me get this figured out!

Thanks in advanced!


You need a true Dual rail power supply - That is to say (+V) - 0V(GND) - (-V) The +Ve must be a positive voltage relative to GND and the -Ve must be a negative voltage relative to the GND.

Not the answer you're looking for? Browse other questions tagged or ask your own question.