Hi,

Could anyone please help me with this question -
What are the differences when developing for a small embedded system that uses a microcontroller such as an Atmel AVR versus a large embedded system that uses microcontroller such as ARM Cortex-A8 or PowerPC?

 

One is small and will take little time to finish, one is large and will take more time to finish. I am not quite sure what are you asking?

On a professional level, when you develop something large, you would have a group of hardware designers and a group of software coders, plus a supervisor who should know both. These two teams meet to discuss the the technical details that need to be met to fulfill the specification of the product, this specifications could also change if really neded to get the thing working. After the prototype is made, the coders make initial code to make it work on some level, then the hardware undergoes further tests like temperature, humidity, EMC, etc. Meanwhile the rest of the software gets done and you create user manuals, datasheets etc. Then some more testing of the software, and then you sell the thing.

Compare it to a simple microcontroller, where typically one person does all these jobs, so the demand for communication and cooperation is much lower. (unless you´re schizofrenic )