Hi,


> N STEENKAMP [M.ING E&E] wrote:
> >
> > Hi,
> >
> > Last week I went to an Atmel AVR seminar for the first time.  It was
> > interesting to see their angle of approach : They are really serious
> > about competing head-on with the PIC.  All through the seminar, the
> > presenter was pointing out the PIC's inadequacies.  At one stage he had a
> > slide comparing a 16 bit subtraction on the PIC and the AVR.  I have
> > never seen such a long 16 bit subtraction routine on a PIC in my life!
> > It must have been at least 20 instructions!  The AVR routine was 2 or
> > three instructions.  To be fair, the AVR would still beat the PIC on a 16
> > bit subtract, even if they compared it to an optimized subtraction
> > routine, but not by such a large margin.  And of course he did not
> > mention the inefficient table read until he was asked about it.  Those are
> > the ways of marketing...
> Speaking of marketing, was the subject of I/O manipulation speed ever
> initiated by Atmel ?

It was mentioned, yes.  Someone asked about it and the presenter
mentioned the SBI (Set bit in IO Reg) and CBI (Clear bit in IO Reg)
instructions.  These do take 2 clock cycle, though.  So there the PIC
beats the AVR.  Although, an AVR running at 1/2 the speed of a PIC would
be able to handle the same rate of IO change as the PIC, courtesy of the
1-clock-cycle-1-intruction-cycle mechanism.  I really wonder how they did
that!?!

> >
> > We did get an AVR develoment board - which is quite nice - and a 1200 to
> > start playing with.  They are also planning on adding loads of different
> > devices and peripheral options in the ?near? future.
> > What I do like about their core, anyway, is the true RISC architecture
> > (no more moving to W before doing a calculation)
> Above can easily be done on pic with two instruction macro.

Very true, but it is not only a matter of typing less.  The AVR
instruction only takes one instruction space (16 bits), while the PIC
macro still takes two intruction spaces.  The AVR code is thus more
compact.


> > , the support for >8 bit
> > arithmetic and the large number of test and branch instructions (no
> > more btfss - goto combinations).
> Above is also done on PIC using special instruction Mnemonics, the
> difference is that where as Microchip market usually 35 instructions,
> Atmel start with 16 bits(same as PIC17Cxx) and subdivide some
> instructions types into the jump variants etc. Atmel call this part of
> their instruction set, where as with Microchip you have to be in the
> know (use the "special instruction mnemonics") or using the PIC17Cxx
> devices to be aware of these similarities.

Same argument as above.


I must admit that I have no PIC17Cxx experience.  I am making my
observations relative to the 12 and 14 bit cores.

Niki