PIC Microcontroller

PIC Microcontroller

The PIC microcontroller (PICmicro or in the terminology of the manufacturer)
are a family of microcontrollers Microchip society. These microcontrollers are
derived from PIC1650 originally developed by the microelectronics division of
General Instruments.

The name PIC is not officially an acronym, although the translation into
"Peripheral Interface Controller (Peripheral Interface Controller) generally
accepted. However, at the time of the development of PIC1650 by General
Instruments, PIC was an acronym for "Intelligent Programmable Computer" or
"Programmable Integrated Circuit."

Implementation

Implementation

A microcontroller is a unit of information processing-type microprocessor
with the addition of peripherals to achieve erection without requiring the
addition of annexes. A microcontroller can operate autonomously after
programming.

In this sense, the PIC is particularly well endowed as they integrate program
memory, data storage, ports of entry-exit (digital, analog, PWM, UART, I ² C
bus, and so on.), And even clock, although bases outside of time can be used.
Some models have port and processing units of the USB.

Architecture

Architecture

The PIC comply with the Harvard architecture: they have a program memory and
data memory separated. Most instructions occupy a word of the memory of the
program. The size of these words depends on the model of PIC, while the data
memory is organized into bytes.

The ICPs are components known as RISC (reduced instruction set computer), or
microprocessor instruction set reduced. More on reducing the number of
instructions, easier and faster is decoding, and the sooner the device operates.

An instruction cycle lasts an ICP 4 time clock. Most instructions last cycle,
except jumps that last two cycles. It will reach high speeds.

With a quartz 4MHz (or the internal clock), one obtains 1000000 cycles / second,
or, as the PIC runs almost 1 instruction per cycle, except for jumps, it gives
an output of around 1 MIPS (1 million instructions per second).

Most of the PIC can be clocked up to 20 MHz, which is a processing speed more
than honourable for a microcontroller.

Programming

Programming

The ICPs have several technologies ROM program memory: EPROM, EEPROM, UVPROM, flash.

The programming of PIC can be done in several ways:

• Through a dedicated programmer (for example: PRO MATE of the company
  Microchip)



• By programming in-situ. Just correctly wired microphone on the
  daughter board for a simple serial link suffice. For this there are
  several open source software (software + interface to oneself) or
  commercial (eg ICD2 Microchip).

Debugging

Debugging

Several options are available to debug a program written for a PIC microcontroller:

• Simulator;


• Emulator;


• In-circuit debugger.

PICs Families

PICs Families

PIC models are marked by a reference in the form:

• 2 digits: PIC family;



• 1 or 2 letters: type of program memory;



• A number: PIC model in the family.

For example, the 16F84 microcontroller is a family PIC16, flash memory (F),
84 model.

PIC10 and PIC12
These are components recently. They specifics as to
be extremely small, simple and economical.

PIC16
Components of the middle ranges. This is the most family
provided.

PIC17
Range between PIC16 and PIC18. This range is enriched by
Microchip. It supports C compiler.

PIC18
This family has a set of more comprehensive instruction as it
includes on the order of 75 instructions. This extended range of instructions it
can run C code compiled so much more effective than previous families. They can
be used with an oscillating quartz up to 48MHz.

PIC24
This family was released in 2004. It is programmable in C
like all other PICs.

Some features worth noting:

• Programmable with the MPLAB C30 compiler derived from GCC 3.3 (all
  families of 16-bit microcontrollers from Microchip can be programmed
  with this compiler);



• Has a JTAG port.

PIC32
Out in November 2007, the PIC32 microcontrollers are 32 bits.
They are based on the MIPS M4K heart.

dsPIC30/dsPIC33
The dsPIC (digital signal PICs) is the first
microcontroller from Microchip society that has a 16-bit architecture (the other
being 8 bits). It is suitable for applications in signal processing and can thus
replace a DSP.