Go to and you should find it.
Jim
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On Jan 21, 2019, at 8:49 PM, k7da <
k7da@...> wrote:
Jim.?? glad you took the time to explain this, but somewhere
along the line i missed the jumper cutting.? i am also unable to
find the card that came with the teensy.?? so can you give me (
and others that missed it to) where the jumper is.? it is not
obvious looking at the board.
thanks
dave k7da
On 1/21/2019 2:06 PM, Jim Sheldon
wrote:
Art,
I didn't see a definitive answer yet and I know Jack is super busy
trying to sort out everyone's problems so I'll answer your
question.? The pad in question is shown on the back side of the
Teensy 3.6 (and other Teensy's as well) pinout card that came with
it, as the VIN/VUSB jumper and it says to cut that jumper if using
a battery charger OR external power.? The battery charger isn't
relevant here, but external power is so the jumper MUST be cut.
Now for the reason which isn't readily apparent.
You are powering the Teensy 3.6 from the 5 volt regulator on the
JackAl board.? If you have not cut the jumper and plug the USB
cable in to re-program the Teensy (or for some other purpose like
CAT control or other serial I/O from the USB port) you are also
supplying a nominal 5 volts from the USB port to the Teensy.? The
two voltages will most certainly not be exactly equal as they come
from two different power sources and they WILL conflict with
possible damage to the Teensy's on-board 3.3V regulator and other
circuitry (I know, I destroyed one by doing this before I figured
it out).
So, in this case if you don't cut the jumper, don't connect the
USB cable with the JackAl powered up.? By the same token, if you
follow PJRC's directions and cut the jumper, you will have to
power the JackAl up to get the Teensy operating before you will be
able to re-program it.?
If, like me, you sometimes forget these things then cut the jumper
(recommended anyway) and just remember that you have to have the
JackAl powered up to use the USB connection to program the Teensy
3.6 (or to communicate with it for any reason).
Jim Sheldon - W0EB
___________________________________________________________________________________________________
(Art Olson)
Jack
I vaguely recall some discussion about cutting the 5 volt pad
on the teensy. Is this still necessary or am I off target.?
?
Art N2AJO
