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FAQ.txt
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FAQ.txt
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FREQUENTLY ASKED QUESTIONS
Q1. Why is my LED very dim when I flash it?
A1. Have you used the correct resistor value with the LED?
There are two versions of the Arduino Pro Micro, a 3.3 volt device
and a 5 volt device. The resistor required with any LED will be
slightly different if the supply voltage is different. A 330 Ohm
resistor is typical with most LEDs on a 3.3 Volt supply.
Also, if you have bought a kit of bits including buttons, note that
there will be higher value resistors (usually 10K Ohm) in the kit.
If you use a 10K resistor with an LED, it will just about glow,
but very dim.
Q2. Why is my 7-Segment display showing very strange patterns?
A2. Have you set the polarity in anyio.seg7 correctly?
Have you got a display that is wired differently to others?
Have you connected the power rails?
The anyio.seg7 module supports both Common Anode and Common Cathode
displays. A Common Anode requires a low voltage to turn on the segments,
whereas a Common Cathode display requires a high voltage to turn on
the segments. The third parameter in the setup() function sets the
polarity of the display
import anyio.seg7 as display
ON = True # True for Common Cathode, False for Common Anode
display.setup (GPIO, LED_PINS, ON)
Not all 7 segment displays are wired identically. A way to check
is to individually power each LED segment through a resistor
and use this to check which pin connects to which segment,
and adjust your LED_PINS constant appropriately.
You should also check that you have wired the 0V and the VCC
from the Arduino Pro Micro correctly to your breadboard (usually by
running wires from those pins to the power rails on the breadboard)
to ensure that the display is correctly powered.
Q3. Why doesn't my button seem to work?
A3. Have you wired the power rails correctly?
For the button to work correctly and reliably, you will need a 0V
connection for when the button is pressed, and a 3V3 connection
to connect your pullup resistor to. Have you wired the 0V and VCC
of the Arduino Pro Micro to the power rails of your breadboard
correctly? Also, some larger breadboards have their power rails split
into two disconnected halves, and you have to also jumper a wire
between those two halves if you want to use the full length of the
breadboard