Xbee ser.1 problem: oscillating digital inputs

Wireless & IoT
1

Hello everybody,

I’m working on a project where I want to send SMD tactile switch button pushes over Xbee to MAX/MSP. Communication is working to MAX, but two of the five inputs oscillate between on and off, if I hold my fingers on the contacts on the xbee the oscillation will stop.

I connected the pushbutton to ground, so when a button is pushed the digital input is connected to ground. The internal pull-up resistors are enabled.

Does anyone have any idea what might be the problem?

Thanks in advance!

Freek

2

Just some basics:

When touching pins solves to problem I suspect an oscillation.

How long are to wires between the buttons and the XBee inputs? Maybe add a small cap on the XBee inputs.

Did you put a cap on the power to the XBee?

Are you sure the internal pull-ups are enabled? Measure to pin with a voltmeter. Maybe try adding external pull-ups so well.

3

Hey,

thanks for the comment, I used a regulated power supply and checked the internal pull-ups. Found out that pins 12 and 15 don’t have internal pull-ups, which are the only free pins left. Added the external pull-ups and everything works fine.

Thanks!

4

Great its fixed.

cheers