piclist 2002\08\25\152726a >
Thread: Wondering about the avr...
face BY : Jim email (remove spam text)

  "If one takes a 12C508A  f.ex. and uses internal
   RC then what clock frequency does it run on for
   FCC purposes ?"

Gee, I can see major spurs (spurious) being created
at the 'clock' frequency (what ever f the proc core is
clocked at), determined by whatever the RC combo works
that out to be, and if you *fail* to think that just
because a uP w/o a crystal *has* no oscillator then it
will be the first visit by the FCC in one of their field
enforcement bureau vans with a spectrum analyzer that
points out the errors of your ways ...

If in doubt, "range check it" ...

**Seriously** -

- the PIC with everything on-board has GOT to be the one
of the cleanest uPs on the market. I have a Z80 design
that spews garbage EVERYWHERE - but it's not marketed
or sold so I can get away with it. It creates noticable
'spurs' (carriers) throughout the HF spectrum and even
causes noticable herring bone patters on VHF-Low TV
channels ... the Z80 design uses every peripheral IC in
the Z80 family plus RAM and EPROM IC. The board design
is only two-sided  w/no Ground plane and the traces
are run nearly everywhere!

Ground and power are .1" parallel buses running under
each IC, joining together to the main .1" bus. Bypass
caps are present at each IC.

It is also very noticable *which* routines are running
in the code - there are several "phase-locked loops"
in software that lock onto externally supplied
data (Motorola trunking signals) and so the CPU
is constantly servicing interrupts due to timers
and edge transitions, perfroming timed scanning of
keypad and updating data to LCD display *desides*
doing error det and corr for a rate 1/2 convolutional
data decoder and a block parity checker.

RF Jim

   "Our ability to manufacture fraud has exceeded
    our  ability to detect it."

    - Al Pacino as Viktor Taransky in the movie 'Simone'

{Original Message removed}
<00da01c24c6d$7d370820$0100a8c0@piii500a> 7bit

See also: www.piclist.com/techref/index.htm?key=wondering+about
Reply You must be a member of the piclist mailing list (not only a www.piclist.com member) to post to the piclist. This form requires JavaScript and a browser/email client that can handle form mailto: posts.
Subject (change) Wondering about the avr...

month overview.

new search...