[SOLVED] Launchpad Pin 3 vs Pin 8

[xeebot 5]

Good evening!

I'm using a CC3200MOD Launchpad - I have tested this on two of those boards, as well as on a CC3200 Launchpad. The results are the same each time.

I have a Reed switch on a bread board.

If I connect to Pin 3 (header row one, 3rd pin down from the top), the reed switch value never changes. (results not expected)

If I change the jumper wire to Pin 8 and change the sketch from 3 to 8, the Reed value changes state with the presence or removal of a magnet. (expected result)

Can anybody point out my error? From the pin map below, the two pins should function the same.

Pin Map

 

 

[xeebot 5]

Please note, Pin 3 is RX on the Launchpad, so I am wondering if the pin is reserved for that reason or if there is something else going on - hopefully, it isn't reserved, as RX is not needed when the BIN is already uploaded and running

[energia 484]

This pin is also connected to SW3 aka PUSH1. There is a 10k pulldown on this pin. How do you have the read switch connected and how do you set pin 3 as input in your Sketch?

One thing to try is to use your existing code with pin 3 as input and then push SW3 and see if the value changes in the Serial monitor.

Robert

[xeebot 5]

Sure enough, pressing PUSH1 and it reads properly.

The reed switch is connected to pin 3 via a jumper wire to the breadboard:


  const int Hall = 3;
  pinMode(Hall, INPUT_PULLUP);
  int HallValue = digitalRead(Hall);
  Serial.print("Hall Sensor Value:  ");
  Serial.println(HallValue);

I've got the Piezo working (PWM), so I'm swapping out the reed switch for a Hall sensor. Once I've got that working as expected, I'll compile and should have firmware that can test all the components on my board. Will post something in this forum documenting all the separate little pieces once I have that working.

Thank you VERY much for taking the time to answer all of the questions we noobs keep throwing out here. It makes a big difference!

Edited January 5, 2018 by xeebot
left out one line

[energia 484]

The internal PULLUP resistor is to weak to effect the 10K PULLDOWN on SW3. You'll need a 1K pullup connected to the reed switch. See schematic snip for the CC3200 LaunchPad below:

 

[xeebot 5]

100% on target, sir!

I had actually switched over to a hall sensor on pin 8 with a 10k resistor and just switched to 3.

Works like a champ.