introduction in micro controllers

8/7/2019 Introduction in Micro Controllers

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Introduction in Microcontrollers

WHAT IS A MICROCONTROLLER?

The microcontroller definition from Wikipedia:http://en.wikipedia.org/wiki/Microcontroller

"A microcontroller (also microcomputer, MCU or C) is a small computer on a single integrated

circuit consisting internally of a relatively simple CPU, clock, timers, I/O ports, and memory.

Program memory in the form of NOR flash or OTP ROM is also often included on chip, as well as a

typically small amount of RAM. Microcontrollers are designed for small or dedicated applications.

Thus, in contrast to themicroprocessors used in personal computers and other high-performance or

general purpose applications, simplicity is emphasized. Some microcontrollers may use four-bit

words and operate at clock rate frequencies as low as 4 kHz, as this is adequate for many typical

applications, enabling low power consumption (milliwatts or microwatts). They will generally have

the ability to retain functionality while waiting for an event such as a button press or other interrupt;

power consumption while sleeping (CPU clock and most peripherals off) may be just nanowatts,

making many of them well suited for long lasting battery applications. Other microcontrollers may

serve performance-critical roles, where they may need

to act more like a digital signal processor (DSP), with higher clock speeds and power consumption.

Microcontrollers are used in automatically controlled products and devices, such as automobileengine control systems, implantable medical devices, remote controls, office machines, appliances,

power tools, and toys. By reducing the size and cost compared to a design that uses a separatemicroprocessor, memory, and input/output devices, microcontrollers make it economical to digitally

control even more devices and processes. Mixed signal microcontrollers are common, integratinganalog components needed to control non-digital electronic systems."

We have selected the PIC16F877A microcontroller from Microchip Technology to be our mainMCU throughtout the experiments on the MCULab2.0. The PIC family series is very popular MCUs

due to their availability, low cost, simplicity to design and the great Internet based litreture tosupport them.The PIC16F877A is the superset MCU in the PIC16 family of MCUs, it has most of the features and

it was the highest end device in the PIC16 family untill the new PIC16F887 released, it is now

recommended by Microchip for new designs. The differences between both the PIC16F877A and

the PIC16F887 are very limited. We will update our experiments to the new one, however, this

manual still use the old PIC16F877A in its programs.


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PIC16F877A pinout

The pinout of the PIC16F877A is:


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Liquid Crystal Display (LCD-Displaytech 162A )

LCD Displaytech 162A consists of a LCD panel, a controller IC (KS0070B) and a back light LED.

The LCD module consists of total 16 pins in which, 2 are for power supply, 2 pins for BacklightLED, one pin for contrast adjustment, 3 pins are for control signals and 8 pins are data pins. In order

to display any data, we need to do certain initiations. The following are the main three steps indisplaying any data in the LCD display.

1. Initializing LCD by sequence of instructions2. Executing commands depending on our settings in the LCD3. Writing data into the DRAM locations of LCD in the Standard Character Pattern of LCD

LCD was successfully interfaced with PIC16F877A microcontroller

The circuit diagram


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introduction in micro controllers

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