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Assembling a Spartan breaduino, We will be minimal in this assembly
hence its spartan. We will use the ATMega328 microcontroller,
just like this one, we have one already embedded in breadboard
to save a bit of time. This circuit has a mark or a slot
on one side, in this case is here, which marks pin 1.
To put this to work, we're gonna use two wires and a resistor.
This is the minimum we can arrange for this microcontroller to working.
Well let's start by wire the negative, we are following the circuit reference sheet
It says it is fed at pin 22 ...
So the pin 22 is here on this side (let's see) is the seventh pin from here
(one, two, three ... seven) is here, here will be the negative and go to the negative "rail".
The positive is two pins after, lets move this up
to have more space, the positive is two pins after ...
Some "net" schemes include a link, notice there's a pin interval.
Some "net" schemes include an extra wire on that space
I do not advise, it is not necessary and
I not advise because this is the AREF, and depending on the circuit configuration
it may be a voltage output. If so things will not run well.
Also in reference sheet, we see here that it also has two power pins
on this side. In a normal assembly we would wire this,
on this assembly as this will not require a lot of current it will be
enough for this to work. Moreover, we need a resistor,
This is a 10K resistor, wired as a pull-up on reset pin.
The reset pin is this one
The reset is active low so if it is at a low or zero level this circuit
will be in reset, we do not want that, so we have to pull this pin to
positive. This resistor does not have to be
10k, its got to be a high resistor, its not appropriate to be lower than 1200 ohms.
That said, this is the minimum configuration,
here we have the breadboard, microcontroller, one resistor and two wires.
With this spartan breaduino this was already able to function.
However little more going to do, so it would work but we wouldn't see nothing.
Lets give it something to do and that we can see.
Lets add to this assembly, a LED and a resistor.
This is a normal LED and a 180 Ohms resistor.
Wire the resistor to digital pin 13 (corresponding to pin 19 of the circuit)
On side right near the power supply
and the other somewhere outside the circuit
notice the LED has a longer pin, this should be positive
and the other negative for it to work
The resistor will limit the LED current, so we wont burn the LED or the circuit.
so it's a 180 Ohms resistor.
We want this to light when the pin is high (5 volts)
So the longuer led pin will conect to the microcontroller
through the resistor, and the other pin will negative.
In breadboards lines... these lines here
are common links so, the resistance and the LED are connected
in a shared line. Having said that, we just need to connect it to the power.
To connect it to power, we have an ATX power supply that is regulated and stabilized,
its a computer ATX/PSU. We will be using the 5 volts it provides. You can also
use a USB mobile phone charger, because the USB chargers are usually
regulated and stabilized. We will use here 2 more wires ...
Wiring the negative to the other breadboard which is aside and is already connected to the PSU
although the source is turned off at this time.
It is advisable to do this with the power off. And the positive to 5 volts on the other breadboard.
Okay this was just a matter of pulling power here.
With this it can now run and we can already see it doing something because
Here we have a led that it will be able to blink. This circuit has been programmed previously
to be able to blink one LED on pin 13. Some assemblies include on this side
a quartz crystal, which is an oscillator or clock.
The circuit normally operates at 16MHz at 5V, at 3.3V it also works. The specification
does not recommended 16 MHz, recommends 12 or 8 I'm not sure ... but we have seen
several people working with it to 3.3V and 16MHz, I personally am using the
3.3V/16MHz for several months with no problem.
Anyway usually the net assemblies include here a quartz crystal
it is not absolutely necessary, we can run this without that crystal.
Without the crystal it will revert to an internal oscillator that is usually 8MHz.
However these circuits so bought virgins sometimes come with a 1 MHz internal oscillator,
this is the case, it will be 1 MHz. And also usually they come with no bootloader, which means
that if we put this into an arduino we would not be able to program it.
Because first we have to put the bootloader in for this to work on the arduino board.
Well let's give power to it. Here we have the Power On button
Ok, Here is the spartan breaduino flashing the LED
as programmed, Simple.