PIC Micro's For Beginners
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PIC's are small
programmable IC's that have many pins which can be turned into
inputs and outputs for any range of tasks. With this incredible
feature, coupled with many other 'built-in' peripherals,
PIC micro's
have infinite uses for projects and applications.
There are many ways to program a PIC, wether it be the
type of programmer or the compiler (software used to develop
programs), the first couple of stepping stones entailing programming
your first PIC are usually where people give up. This basic guide is
designed to get you off your feet, and program your first PIC, by
not using dodgy programmers or software, just explaining the raw
real truth of what are the best tools to use for PIC development.
Before I get much further, I would like to clear one
fact up, there are different families of PIC's, in particular, the
16Fxxx range and 18Fxxxx range. There are others, but these two are
the most popular and supported. Briefly said, Microchip never
discontinues a product range. They offer continual support
from the date of release, until the present day. With this in mind,
there are many types of PIC's out and about, some are very old. The
16F range is old, and while they have no errors, they do have flaws
in regards to the way memory is handled in particular. This is why I
really recommend using 18F PIC's, they are newer, operate faster,
and have a lot more features ready to go.
To start off with, I bet your wondering how we control
the state of pins on a PIC, first of all, lets have a look at the
pin-out of a
PIC micro, in this case the
18F1320. Here's what one looks like in real life;
And this is the pin-out of the PIC (pin 1 can be
identified as the one to the left of the indent on top of the IC)
It looks like jargon if you haven't played with PIC's
before I know... The next learning curve is the PIC's pins are
grouped into ports. As you can see, pin 1 is RA0, this means
PORTA pin 0. Pin 2 would be
PORTA pin 2. As you work your way around the PIC, you will notice
that the pins for each port are not necessarily sequential according
to their physical location, and you will also see pins labelled MCLR
(pin 4), Vss (pin 5) and Vdd (pin 14), amongst others.
These newly discovered pins are the "vitals" for the
PIC to operate. Vdd is the positive supply, Vss is earth and MCLR is
a hardware reset pin, and must remain high or else the PIC's program
will reset. The supply voltage for PIC's is typically 5 volts, some
can go lower then that, but for all tutorials besides those that
specify different, Vdd refers to 5 volts. Your
power supply should
be your first project, and it utilises a
7805 IC which has three pins, input, ground and output. Put
simply, it turns any voltage above 6.5 volts and up to 12v into a steady and very stable 5 volts. More can be
found on the
how to build a voltage
regulator tutorial.
Next Part of the guide - Your First
Program, click to
continue
