On Feb 18, 2007, at 7:12 AM, Jake Vickers wrote:

>> why a C chip? (OTP)
>>
> I'm working on a specific idea. I saw some stuff on the 'net for
> controlling relays (or LEDs, whatever) from a serial port utilizing
> a PIC chip. the code was written for a 12C671...

Not a bad reason.  But as your first "homework assignment" for
"learning about microcontrollers", I assign the following: :-)

1) What features of the 12C671 are important to your project ?
2) Which reprogrammable ("F" series) part comes closest to
    matching the capabilities of the 12C671
    2a) Which F-series part comes closest to meeting your
        project requirements?  Is it the same?
    2b) Which F-series part that meets the project requirements
	   is easiest for you to get at your location?
3) What differences between the 12C671 and the part you've found
    will require specific attention to port the old code?

You might be able to make use of your OTP 12C671 (I assume it doesn't
have a clear window in the top, in which case it's UV-eraseable) by
overwriting your LED-blink code with 0s (NOP) and putting new code
in the as-yet-unprogrammed section of the EPROM.  that'll depend on
exactly how your programming SW works, but it could work...

> That's where the Internet is a speed-bump. Everything I've been
> reading on how to get into PIC programming uses the 16F84 as
> examples. Old write-ups and how-tos, which have not been updated
> for new technology I guess. Since all of my knowledge about PIC
> programming is coming from 10-12 web pages, I'm stuck on a
> slow-track if the information is out of date.

Well, books or school classes wouldn't necessarily be any less
out-of-date; that doesn't make them useless...  Very little of what
you learn about a 16F84 is USELESS; it's just that it should be
applied on modern technology rather than actual 16F84 chips...

BillW

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