One important feature missing
If you hadn’t noticed in the pin description, there was no mention of RX or
TX pins. This is because unfortunately the ATtiny84 doesn’t have a
hardware UART. The UART is used for serial communication, whether it’s
for programming, or printing messages to the serial window. You might be
thinking “But doesn’t the USB connector provide communication between
the ATtiny and computer?”, and you’re right; it does. To keep the
bootloader size as small as possible, the bootloader only allows for USB
programming. For serial debugging, you’ll need a USB cable and a USB-to-
Serial adapter, and Software Serial library to send messages to a
computer. You can learn more about serial communication here.
Hardware Assembly
To use your Roshamglo, all that’s needed is to solder in the battery clips.
To insert the battery clips, you’ll need to turn the board to the side with the
pictures of the batteries and push the battery clips into the holes. Make sure
that the metal tab on the ends are facing away from the center of the board.
Make sure the battery clips aren’t touching each other! To make sure they
won’t short against each other, make sure the clips sit flat against the circuit
board.
After the clips are installed, you can turn the board over and solder all of the
joints on the top side of the board. When they’re all soldered together, they
should look like this:
Installing the batteries are easy, but as you install the batteries, make sure
you insert the batteries in the same orientation as the silkscreen image
between each pair of battery clips. After the batteries are installed, you’re
all set! You can move the switch on the left side of the board to “ON”, and
you should see the red power LED come on.
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