TNC-Pi User Guide
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6/25/2017
on top of the USB connector just to be on the safe side. You can then solder
the pins that come through the top of the board.
These pins will allow you to stack a second TNC-Pi on top of the first one if
you choose to do so.
Now install the 2 x 2 jumper (JP3 and JP4). If your board has a JP7
location, also take a short piece of wire and solder it in here to make a
permanent jumper.
Note: If you are building a TNC-Pi 2, none of these
jumpers are needed or included in the kit. If you are building a newer kit
from the original version JP3 and JP4 will also be missing, but you may need
to put a wire across JP7.
I’ve included 2 4
-
40 screws and a 5/8” spacer. If you have one of the
Raspberry Pi Rev. B and the original TNC-Pi kit, or if you have the Rev. B+
or Pi 2 and the TNC-Pi 2 kit, you can use this to provide some additional
mechanical stability by putting it between the hole in the Pi and the hole in
the TNC-Pi. If you have a Pi B+ board and the original TNC-Pi kit, these
parts are not needed. There will be plenty of mechanical support from the
extra USB jacks on the Pi board, but you will want to use insulating tape on
these jacks to keep them from shorting the TNC board.
If you are stacking 2 or more
TNC’s you might also find it preferable to use a
spacer that is a male to female, rather than female to female. These male to
female spacers are available on the TNC-Pi website.
Now install jumpers at JP4 and JP3.
They should be installed so they are parallel to the body of the 2x13 pin
connector.
If you are building a TNC-Pi 2 or newer original TNC-Pi, none of
these jumpers are needed or included in the kit.
Leave the board connected to the Raspberry Pi and power up the Pi.
Check the voltage between pin 5 (negative) and pin 14 (positive) on
U3. It should read about 3.3 volts. With the notch at the top of the
chip, these pins are the ones half way down the left side (negative)
and right side (positive) of the chip.
If the voltage check is not successful, find and fix the fault before
proceeding.
Power down the Pi and
remove the TNC-Pi board from the Pi,
then install the 4 ICs.
You may wish to bend the pins of the four ICs slightly inward to facilitate
inserting them into their sockets.
