All,

 There are two very obvious reasons why a PIC would appear to have such a
 radically different architecture and instruction set versus the typical
 microcontroller.

 1. The PIC uses a HARVARD architecture whereas the typical microcontroller
    uses the Von Neuman architecture.   And as far as I know, the PIC is
    the only microcontroller in it's class to use this architecture.

 2. The second thing that is obvious is that the PIC is a RISC processor.
    Whereas the 8051 is a CISC processor.  And as far as I'm concerned,
    this is a definite plus.   I only have to concern myself with about 35
    instructions versus 100+ in the 8051 with about 5 ways to use each.
    For me, the 8051 is way too complicated.  And I have yet to find an
    application where a PIC won't fill the bill.  Of course, I'm not in
    the business of creating extremely sophisticated equipment that uses
    only the PIC for it's main processor.   Most of my applications are
    as adjuncts to a system that already uses a PC or similar computer for
    it's main brain.   I need a bunch of fast I/O which is exactly what the
    PIC was designed to do in the first place.

 Anyway, this is my 2 cents worth on this subject.   Good Luck.


                                                      Regards,

                                                        Jim





> I had a supervisor who had used PICs before, and did not like them.
>
> I've found since then that a lot of people that have significant
> experience in other uControllers, and have touched (but not delved
> into) the pic do not like its code set and architechture.  It really is
> very different from older more venerable processors.
>
> The short of it is that you get to do what your supervisor tells you to
> do.  Since you've been given the task of finding an appropiate chip,
> then there is little harm in throwing in a pic with the others for a
> good comparison.  You may surprise yourself, or you may surprise your
> boss.
>
> Furthermore, there are '51 variants that do everything the 877 does and
> more, often costing less.  The one /major/ nice thing about the '51 is
> the ability to second source.  If you can fit your program on a
> non-flash chip then you'll find the pic may be cheaper.  I suspect that
> like your boss you have bias's.  Don't spend a much time trying to
> figure out how to make him see the light, spend time looking for
> appropiate processors (not just the '51 or pic, try motorola,
> mitsubishi, etc).  Be sure to include in the costing the tool chain
> needed to work with the processors.  It may well be less expensive to
> go for the PIC if only because the c compiler is so inexpensive
> compared to the thousand dollar beasts used for many other processors.
> Then again, it may still be cheaper to go with a '51 compiler you
> already have in house.
>
> Lastly, don't make him take a stand (sounds like you already may have).
>  The more he feels you trust his experience, the more trusting he will
> be of your decisions and contributions, and the more latitude you'll
> have for the next project.
>
> Besides, experience on another processor is a good thing.  You might
> want to go the something other than a PIC simply for that reason.
>
> -Adam
>
>
> Mahmood Elnasser wrote:
>
>>Hi all
>>We are all great fans of the pic, I'm trying to use the PIC16F877 for a
>>project, my boss is forcing me to use 8051, I need 30 I/O lines
>>including 2 serial ports and eeprom space where my F877 fits perfectly.
>>I searched through most of the 8051 family but couldn't do it with a
>>single chip.
>>He argues that the pic has awkward architecture with small memory map
>>and poor support for compilers. Looking at the F877 I think it's the
>>opposite, it has large memory and a great architecture and lots of
>>peripherals and 2 fast, there are also lots of good compilers around.
>>Any suggestions, comments, feedback welcome.
>>thanx
>>
>>--
>>http://www.piclist.com hint: The PICList is archived three different
>>ways.  See http://www.piclist.com/#archives for details.
>>
>>
>>
>>
>>
>
> --
> http://www.piclist.com hint: The PICList is archived three different
> ways.  See http://www.piclist.com/#archives for details.

--
http://www.piclist.com hint: The PICList is archived three different
ways.  See http://www.piclist.com/#archives for details.