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Re: I2C

From: Sandor Ajzenstat   sandorinterlog.com
Date: Sat, 28 Aug 2004 19:59:51 -0700

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Hey Victoria,

I would like to recommend the PIC18C452.  My approach has been to choose
this one PIC and stick with it and I've been very happy with it.

Features:

- 40 pin DIP runs at a max clock speed of 40 Mhz.
- 32 K of  8-bit program memory
- 1.4K of data memory.
- A/D converter, 8 Analog inputs.  10-bit resolution.
- IC2 interface supports master, multi-master and slave modes.
- Asynchronous serial I/O
- Three 16-bit timers and one 8-bit timer.
- Two Capure/Compare  Pulse Width Modulation modules.
- 8 bit hardware multiplier instruction executes in a single instruction
cycle.
- Parallel slave port can directly interface to an 8-bit microprocessor data
bus.


Notes:

I don't know C, so I can't speak for running C code on this chip.

I've never worked with IC2 so I can't speak for its implementation in this
chip, although they sure spend lots of pages in the data sheet discussing
it.

Machine code programming is made easier in this chip than in other PICs by
the fact that you almost never need to be concerned with page boundaries.

There is a flash version, the PIC18F452.  Personally I will not use those
chips because I spent far too long trying to get the tiniest peep out of
them with zero success.  Either I was doing something wrong, or the chips I
was using were at fault. If it was infact the chips, then perhaps they've
fixed the problem in more recent stock.

The data sheet I have for the 18C452 is serial number DS39026B.  It is
riddled with typos and errors.  I haven't looked around on the Microchip
site recently to see if there are any erratta sheets, there weren't when I
downloaded it. Besides the errors, the data sheet is just plain badly
written.  It is truely the worst manual I hope to ever come across.
Hopefully they've updated it.

I would be more than happy to try to answer any questions you might have
pertaining to the 18C452.

It's great to hear from you Victoria,
Take care,
Sandor







(There is a flash version 18F452, and I'm sure it's fine, but I've
personally never gotten it to work)
----- Original Message -----
From: "Victoria Scott" <toria@xxxxxxxxxxxxxx>
To: <arg-list@xxxxxxxxxxxxxxx>
Sent: Saturday, August 28, 2004 6:09 PM
Subject: ARG: I2C


> A! Sent via the Art & Robotics Group mailing list:
arg-list@xxxxxxxxxxxxxxx
> R! Use your "Reply All" to  reply to the list, "Reply" for private
response
> G!
>
> Hey ARG,
>
> Nice to see that the list is perking up again, must signify the end of
> summer fuzziness.
>
> I'm trying to control six devices (wee 'robots' each programmed with
> the 16F819 to move a stepper 180 degrees) with synchronous serial
> communication, maybe with I2C.
>
> So I have my slaves lined up, but i need a good Master (I never tire of
> electronics metaphors).
>
> Does anyone have a favorite PIC flavour for such a task. The Master
> will also be receiving a sensor input (most likely a photocell), so
> AtoD is also a necessary requirement.
>
> I'm still in the throes of leaning C and only been working with the PIC
> for a year (self taught at this point) so go easy please.
>
> best.victoria
>
>
> A!
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