AVR-Chat

On Wed, 2005-11-16 at 23:31 -0500, Charlie Heath wrote:

> Subject: [AVR-Chat] Re: cheap chips , no exteranl crystal, and timing
> > --- In AVR-Chat@yahoogroups.com, Thomas Keller <tkeller1@n...>
> wrote:
> > > On Tue, 2005-11-15 at 22:03 -0800, Reid Smith wrote:
> > > >   The Pic chip requires a 4 mhz crystal in order for
> > > > it to function. I'm building a serial lcd driver and
> > > > want the cheapest chip I can find. It requires in
> > > > order for it to work correctly 6 out and 2 in with error
> > > > checking so any 18-20 pin should work fine.
> > > >  AS may be.  Many of the AVR chips will run at 8 Mhz (which 
> > > > > would be the equivalentof a 32 Mhz PIC) without a crystal, 
> > > > they cost less, and there are a number os AVRs specifically
> > > > designed to drive LCD displays (some offer as many as 100 
> > > > segments of drive).
> > Many PIC's have an internal oscilator.  but AFAIK, none have an 8mhz
> > internal.
> FWIW, the PIC16F88 has an 8-step internal oscillator that tops out at
> 8 Mhz.  18 pins with 4K instructions, hardware USART, 7 channel A2D,
> SPI, I2C slave support, etc, etc.  A nice chip available for $3.25 or
> so.

   A PIC with an 8 Mhz oscillator is giving you 2 MIPs (max) of
performance.  An AVR running with an 8 Mhz oscillator is giving you 8
MIPs (max) of performance.  (and this doesn't even consider the horrible
instruction set and architecture you have to deal with when programming
the PIC parts)  AVRs are simply more flexible, more powerful, and more
easily programmable.

Tom (who admits to be heavily biased)