What's the difference between 8 & 32

[xenobie]

Hello all,

Ok so I have a project, I am not in a hurry to learn and the main purpose here is to learn. But I need to learn the right way. Basically my question is this...

• What is the difference from an Atmel 8 bit uC to an Atmel 32 bit uC from the Programmers Perspective?
  
• As in, what is the difference between a 'hello world for 8bit' and 'hello world for 32bit'?
  
• What is the difference for a complex system written for 8bit and the same complex system written for 32bit?
  

I chose Atmel because this is what I have available and I don't really want to change. Also to save you time, do not explain stuff like, GPIOs, Frequencies, ADC, etc.. etc.. this is all in the datasheet  8)

Thanks all!

 

[william_teter]

The number of bits refers to the size of the data pipe. C will probably hide this from you this, but if you are programming with assembly, you will find if you need to add a 32 bit number to another 32 bit number, you will need far fewer instructions to do so on the 32 bit uC vs the 8 unless it has a special instruction to accomplish this.

The address space will be smaller in an 8-bit uC.. but once again hardware can allow for bank switching and allow the 8bit uC to access just as much memory as a 32bit uC could. For just a simple hello world code written in c, you may not notice a difference... it's when you get into more complex applications that this can become a problem.