> 1. What uController and uProcessor using harvard architecture? > 2. What is the advantages and disadvantages about Von and harvard? Nearly all microcontrollers use an architecture functionally equivalent to a Harvard architecture (from the programmer's viewpoint); generally there are a few features which differ between Harvard and Von Neuman machines: <1> Ability to read from code space: guaranteed on Von Neuman architectures; possible, via kludge, on some Harvard architecture machines. <2> Ability to write to code space: only possible on Von Neuman machines, though some Harvard Architecture machines may be modified to allow writes to code space (often not elegantly, but nonetheless a useful feature during code development). <3> Simultaneous transactions on code/data busses: only possible on the Harvard architectures; can result in big speed improvement. Personally, I think #3 is the best distinction to be made between Harvard and Von architectures; let's see how some common uC's hold up: [for first two columns, Y=do-able with no time penalty, k=do-able via special- ized instructions and/or a time penalty, K=do-able via hardware mods; -=no] 123 uC K-Y Microchip PIC 16Cxx series kkY Microchip PIC 17Cxx series kKY Intel 8x51 series [data space assumed to be the 128/256 bytes internal] YYN Motorola HCxx. k-Y NatSemi COP8 Note that nearly all microprocessors use a single code/data bus, at least externally; while many have seperate code/data caches, the issues raised by this go beyond what can be dealt with in this post.