Zeroplus Arduino starter kit with Logic Analyzer, Manual

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1. As a rule of thumb, sample a digital signal at a frequency at least 4
times the signal’s frequency. When the frequency of the target signal
is unknown, choose a sample rate so that there are a minimum of four
samples points per cycle (2 when High, 2 when Low). You can display
the number of samples on the waveform in the menu option m> customize
waveform area m> waveform information. How often you record (sample)
the voltage value on each channel is called the sample speed. A higher
sample speed ensures that you are not missing anything. Too high and
you’ll fill the memory with unnecessary samples. Too low and you’ll miss
a lot of information, resulting in a waveform which is not a correct
representation of the real signal.
2. How to determine whether a certain voltage should be read as a 0 or a
1? By comparing it to a reference value, also called the trigger level.
Anything below that value is a 0. Anything above it is a 1.
3. Adjust the trigger position to capture more data before (pre-trigger)
or after (post-trigger) the trigger event.
4. It happens because the channels are not updated at the same time.
Look at the code, you can see that in the first counter function it is
written PORTB = bus_counter whereas the other counter updates each pin
with digitalWrite(). digitalWrite() updates the pins one after another.
PORTB updates all pins at once.
REMARKS
REMARKS