I got a doubt about the width of internal data bus of AVR controllers connected to flash memory. I was mainly referring to Atmega328. Datasheet says (Page 17) "Since all AVR instructions are 16 or 32 bits wide, the Flash is organized as 2/4/8/16K x 16.". That means flash memory data bus width must be 16 bit? I could not see anywhere mentioning about 16 bit wide program memory data bus (Of course internal to the controller). But bus for RAM seems to be again 8 bit. Just want a clarification.
BitThe 8-bit AVR family is based on a (modified) Harvard architecture, where you have dedicated program and data storages. The data path to program memory is indeed 16-bit, while it is 8-bit only to data memory.
The funny part is, that in the beginning Atmel points out, that these are 8-bit CPUs. This makes them look very competitive when compared to other 8-bit products like 8051 or Rabbit. Due to the 16-bit program data path the AVRs perform very well in benchmark tests. Later, when 8-bit sounds a bit old-fashioned, Atmel decided to call them 8/16-bit CPUs.