Hardware Bug?: Teensy 3.1 Power Up / Boot Problem - Touch Pin 33 !!!

amtink

New member
Hello,

my name is Andre. I am developing a Standalone AVR Programmer and Test Controller for
testing our thousand PCBs.

While assembling the first Testcontroller PCBs i run into the problem that
the Teensy won't power up. I checked the Supply, everything is fine.

For Testing i run a simple LED Blink program.

To find the problem, i start to solder one pcb by hand and test after each component.
I nearly use every pin of the Teensy.

teensy31_bottom.jpg

That is the Board:

teensy31_tctrl.jpg

Finally i found the problem: it is Pin 33.
This pin is also claimed as a Touch sense Pin.
In my case the Pin is connected to a Tactile Switch with a Pull Down Resistor.

Schematic_1.jpg

If this Pin is not connected, the Teensy boots up and the program is running.
I verified this with the other boards too.
I checked the other Pins too; i solderd a capacitor between Pin 15 and GND. This works fine.
But the same Capacitor between Pin 33 and GND doesn't work.
I also tested the Teensy alone

Conclusion: I could verify this problem with three brandnew Teensys on my PCB and even when I directly connect a cap to that pin, without another PCB.
So, something on the Teensy must fixed!

Regards,
Andre
 
Ah, i am sorry. I search, but didn't found this thread.

So the Admin can move or delete this thread.
 
Back
Top