Heres a simple AVR code using C language to flash a single LED on PORTB

I started looking into programming PIC's with C a couple of years ago and can see that the syntax is quite similar.

Be sure to keep us posted of your future endeavors!

Hi Gav,

What do the annotations |,& and ~ mean ?

PORTB |= 1

PORTB &= ~

I ask as this looks essentially C to me and may be a good way for me to learn it ( Damn ... I just know I'm going to get an arduino now )

Jay

Hi Jay

Has far as Im aware there is a slight difference between AVR and Arduino, the Arduino includes a cross platform IDE which will get you started quicker. Both use the C language but with some differences. (abit like Swordfish and Proton both Basic languages but slight differences)?.



The code that you pointed out Jay are bitwise operators in C as all I wanted to do was change bit0 of PORTB, the diagram below might help explain the bitwise operators in C better.

The one bitwise operator that confused me when I saw it was "~" bitwise operator but once you understand how it works its easy enough. The "~" is a bitwise complement (bitwise NOT), in other words this operator works like this:

So if we take the binary value 1.

00000001

Then if we ~1 using the "~" operator, this will flip the bits so the value is now.

11111110

Hope that helps you understand how the "~" operator works. the others which are "&" is a bitwise AND, and the "|" is bitwise OR operator.




You could also write C code like this:



all will set PORTB bit 0 high (logic 1).

Thanks Gav thats very helpful, I've yet to find any really good tutorials on C, I find it's syntax quite confusing what with all the parenthesis brackets etc.

Also can you recommend a starter board for and AVR ?


Thanks

Jay

Your right Jay I found it difficult finding a good tutorial on C too, spent alot of time searching google and just picked up bits of the syntax along the way, I can share some PDF files Ive come across which might come useful?





My knowledge of AVR development/starter boards are very slim if im honest, a friend of mine has the AVR STK500 board (cheaper on ebay),

comes with a built in programmer and alot of options for different types of Atmel microchips, but the board only comes with 8 buttons/leds, but I think there is a replacement out for this board now called STK600.

Heres the introduction PDF file for the STK500 if you are interested?:


From a personal view I would recommend getting the AVR ISP mkII programmer, very cheap (abit like the Pickit2, hence the word "abit") but there is one down-side of this programmer it doesn't supply power to your projects unlike the pickit2.. but easy enough to connect to a bread board, One other note that I have found with this programmer is that all your projects need a on board power supply (a simple voltage reg would do the trick) As there is what is known as a power supply buffer on the programmer, basically so the programmer knows if your Atmel microchip is a 3.3volt or 5v microchip.

Thanks Gav they are very very helpful and appreciated

I'll check out ebay and get a programmer this evening, any recommends for a good Atmel starter chip ?

With regards to the AVR programmer you might like this

Its by Dave Jones .... I love his channel on you tube ... He's a nutcase ... Very clever guy though,

HaHa yeah Dave Jones, I like watching his Blogs.. Quite interesting! (funny enough I was going to post that video).

Ummm ive just been using a 28pin - ATmega168 (ATMEGA168-20PU) seems to be good enough for what ive been messing with

Heres a good tutorial for AVR

http://imakeprojects.com/Projects/avr-tutorial/

How have you found the learning curve of using AVR's with C as opposed to pics in basic?

Still prefer Basic (Swordfish) I have to say and PIC microchip, this was just an adventure. C language is harder to learn. The syntax of C as Jay pointed out is confusing, there seems alot of librarys out there for AVR C language to a company you with building your projects but a personal view I would'nt say I found one I was overwhelmed with, especially when trying to add a LCD to one of my project. In that case I guess you cant beat the support you get with Basic (Swordfish) and the librarys (modules) that you get.

I dont really want to go into the Pros and Cons of the two microchips but heres a good video

Thanks for that extra info Gav. I am certainly not someone who shuns Atmel microcontrollers or arduino's or anything. For me, I just started out with pics and it has worked very nicely! I am sure that if I had started out with AVR's that I would still be in the same sort of position

Same here Brad I started with pics and its working nicely!, just thought I would try the grass on the other side as they say!! hehe!