OK my question begin with what is difference between ATMEL,AVR,ATMEGA series and Arduino..
How come Arduino boards and AVR development boards are similar or different
Most Arduinos (Uno, Mega, Pro Mini, Leonardo) all uses an AVR ATmega microcontroller. They all have different features (The Leonardo have built in USB, the Mega got 73 IO pins), and vary in price and size and package.
Arduino is basically just a big library collection that handles all the low level stuff in the background. Actually, it's all AVR code behind the scenes! The code below is what actually happens in the digitalWrite method:
void digitalWrite(uint8_t pin, uint8_t val)
{
uint8_t timer = digitalPinToTimer(pin);
uint8_t bit = digitalPinToBitMask(pin);
uint8_t port = digitalPinToPort(pin);
volatile uint8_t *out;
if (port == NOT_A_PIN) return;
// If the pin that support PWM output, we need to turn it off
// before doing a digital write.
if (timer != NOT_ON_TIMER) turnOffPWM(timer);
out = portOutputRegister(port);
uint8_t oldSREG = SREG;
cli();
if (val == LOW) {
*out &= ~bit;
} else {
*out |= bit;
}
SREG = oldSREG;
}
You can also run pure AVR code, without having to include the setup() and the loop() methods. This makes your code a lot smaller, but aren't as easy to understand as Arduino code. The original Arduino blink sketch uses 1030 bytes of memory, while an AVR blink uses 178 bytes.
You can easily develop AVR code on the Arduino. The only drawback is that the Arduino pins (0, 1, 2..) doesn't match the physical ports on the ATmega. The original port names aren't written on the board either, so you'll have to look in the data sheet for your specified microcontroller every time you want to use the AVR pin definitions.
I've been looking for an Arduino board that was "a little more". A board that's simple but got all the necessary functions to develop real AVR code in Atmel Studio. I designed a board that support DIP40 AVRs, where the original AVR pinout and the Arduino pinout is written on the board. The Arduino pinout is also "correct" compared to the AVR pinout. Arduino pin 0-7 represents AVR PB0-PB7. Have a look at my Github page, where the Arduino core for it also are uploaded! (pictures down at the bottom).
There are advantages to using raw port registers
e.g.
PORTB |= _BV(PB0); // digitalWrite(8, HIGH)
PORTB &= ~_BV(PB0); // digitalWrite(8, LOW)
Which are much faster, and use less ROM (and RAM).
But it is not easy to understand what the code is doing, and
that will reduce the chance of getting free help. In general,
when asking for free help it is best to do as much of the work
for the helper as is possible.
A macro can also be used in place of digitalWrite(), but I don't
think anyone agrees on them, so again it becomes a problem when
asking for help.
e.g.
#define b0_high PORTB|= _BV(PB0)
#define b0_low PORTB &= ~_BV(PB0)
So in my view, noobs should start with Arduino and expect
to ask for help, but if you have worked with embedded tools
then it's going to piss you off when you see how digitalWrite()
actually works (remember that you don't have to use
digitalWrite() with the toolchain included with Arduino IDE,
you can choose to use it or not).
what is difference between ATMEL,AVR,ATMEGA series and Arduino..
Sounds like a homework question...
Most Arduinos are AVR development boards. You might call them "a subset of AVR development boards that have explicit support for the libraries and environment provided by the Arduino Development Environment." "Arduino" as a broader term includes both the hardware and the (specific) development environment.