On Thu, Dec 27, 2001 at 08:11:55PM +1100, Sean Alcorn - Avion Sydney wrote:
> Hi all,
>
> I'm a newbie to the list. I am just learning about PICs. Thanks to great
> books by people like Myke Predko, Paul Benford, Gordon Macnee, Nigel
> Gardner, Peter Birnie and John Morton, it's all *just* starting to make
> sense to me - thanks guys!
>
> I have now written 3 little projects for the PIC12C508A - one of which has
> been produced in reasonable quantities and shipped without a hitch. I am now
> working on a project that will use the cheapest 18-pin I can find - most
> likely the PIC16C52, 53 or 54.
>
> I have searched everywhere, and I can not confirm if these devices have the
> weak pull-ups on Port A and/or Port B. Can anybody confirm whether they have
> them or not and how to set them?

Nope. They don't. Didn't you check the data sheet?

>
> Also, is the PIC16C52 still made? There is no reference to them on the
> Microchip site, yet I can still buy them from Farnell. Could be just old
> stock.

There are a couple of other issues involved. Each of the parts that you names
use only the parallel programming algorithm. Programming may be an issue.

If the packaging isn't a dealbreaker, then you may want to take a look at the
16C505. Under $2 US in quantity, it's packaged in a 14 pin package. The PORTB
implements weak pullups on 4 of the 6 abailable pins. It also comes with
builtin osillator and reset circuitry so that up to 12 I/O pins are available.

Other than that, the 16F62X series is probably your best bet.

BAJ

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