Mux Chip

[Scott James]

Hi Guys,
I’m in the process of making a failsafe device for a UAV using a Basic Stamp and a few other bits. I picked myself up a MUX Chip as used in the Ardupilot but I’m having trouble getting it to work. After looking at the Ardupilot layout, I noticed that the GND of the MUX Chip in the Ardupilot does not seem to be connected to anything? Is this correct??
Is there a trick to connecting this thing up? Thanks.
I am powering it out of the regulated 5V out of the Basic Stamp (pin 21) .
The Mux Chip and a few 3mm Led’s are the only things drawing current from the Stamp.
Thanks.

[Michal B]

MUX chip in AdruPilot is connected to GND by its pin 8.

[Scott James]

So it is! I the spec sheet for my Mux chip it says, comes in "D or N Package"

This is mine, which I think is an "N" and I think the one in the Ardupilot is a "D"
What is the difference between them?

I have 5V on the VCC pin and the GND pin is connected to ground and the A/B pins is receiving 0V or 5V from one of the basic stamp pins depending wether it is in failsafe mode or normal mode.
But the other pins (1A, 1B, 1Y, etc..) are doing nothing? The are not passing any voltage at all, it is like they are not connected? I though maybe the strobe pin (G) needs to be connected so I tried it and it made no difference.

Does anyone have any ideas?
All I can think is I have the wrong chip for the job.
The rest of the system is working great, Just not the MUX!

Thanks!

[Scott James]

Update!
All working now, I forgot to tie pin 15 (G) on the Mux chip to GND.
With out doing that the chip is basically turned off.
Hmmmmmmmmmmmmmmmmmmmmmmmmmm :)