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----- Original Message -----
From: "dlc"
To:
Sent: Monday, April 28, 2008 11:18 PM
Subject: Re: [piclist] Problem in assembling
>> Ditto with the F84. It is *THE* PIC to learn on, but once you have,
>> every
>> other PIC is cheaper or better, most are both.
>
> I don't see any reason to use this part. It is a real PIC dinosaur.

It is kind of a dinosaur, but it has a couple of advantages over almost all
other PICs for learning:
- Each pin only does one thing
- All the RAM is echoed in all banks

For a lot of people, learning any microcontroller is kind of intimidating.
With only 35 instructions, the PIC16 isn't rocket science to be sure, but
many of people approach it with a lot of uncertainty. While the step up
from the 84 to anything else isn't a big one once you have your head around
the PIC, trying to learn the PIC while your variables disappear every time
you do the mysterious banksel to access a register, and remembering to turn
off peripherals you don't yet understand makes it a lot harder for the
newbie.

Once you know what you are doing, these things are, at worst, minor
irritations, but when you first approach the PIC, they add to a barrier that
already appears to be a lot higher than it is.

For people still married to the 84, the other PIC16s are practically the
same. All offer more peripherals than the F84, and almost all offer more
memory. Except for some of the 40 pin parts, all are cheaper. There are a
couple of little coding things to watch out for, but with a little care you
can use the same code across all the PIC16s. (except the PIC16F54/84 which
is a PIC12 with a PIC16 number). My latest Elmer 160 lesson addresses these
differences, and the experiments run on all the 18 pin 16Fs except the 716
which has no EEPROM (the experiments use EEPROM). Unfortunately, with a
bunch of different PICs and 3 development environments, and on the larger
parts, over 1000 meaningfully different ways to organize memory, every
little change requires a ton of testing, so it is going very slow.

That being said, I wonder if the newbie in this day and age shouldn't be
heading right for the 18F anyway. No banking, a lot of the 16F irritations
are gone, and prices have reached the point where it is hard to tell the
difference. There is no 84 equivalent so you need learn to turn off the
analogs right away, but there is none of that annoying banking, and most of
the quirky instructions have been fixed. The main thing lacking is example
projects.

72/73 de WB8RCR http://www.qsl.net/wb8rcr
didileydadidah QRP-L #1446 Code Warriors #35
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> > I don't see any reason to use this part. It is a real PIC dinosaur.
>
> It is kind of a dinosaur, but it has a couple of advantages over almost all
> other PICs for learning:
> - Each pin only does one thing

The fact that a pin *can* do other things does not mean you have to be
bothered by that feature (except for the disabling of some analog
functions, which can easily be done 'by recepy' without knowing what
exactly you are doing).

> - All the RAM is echoed in all banks

The only reason for going to other banks when using a PIC in
'16F84-mode' is to set the TRIS registers, which can (contrary to what
uChip seems to advocate) still be done with TRIS instructions.

So using a 16F628A, 16F630, etc. Has zero (or very little) technical
disadvantage, one one big advantage: killing the chip does not hurt your
wallet so much!

> That being said, I wonder if the newbie in this day and age shouldn't be
> heading right for the 18F anyway.

The 16-bit-cores still lack low pincount chips. And the cute little SMD
10F's (12-bit cores) are much like the 14-bit cores (but with a few
quircks added to the already impressive list for 14-bit cores), so they
are easy to explain to someone who knows his way around with a 14-bit core.

--

Wouter van Ooijen

-- -------------------------------------------
Van Ooijen Technische Informatica: www.voti.nl
consultancy, development, PICmicro products
docent Hogeschool van Utrecht: www.voti.nl/hvu
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>
> ----- Original Message -----
> From: "dlc"
> To:
> Sent: Monday, April 28, 2008 11:18 PM
> Subject: Re: [piclist] Problem in assembling
>>> Ditto with the F84. It is *THE* PIC to learn on, but once you have,
>>> every
>>> other PIC is cheaper or better, most are both.
>>
>> I don't see any reason to use this part. It is a real PIC dinosaur.
>
> It is kind of a dinosaur, but it has a couple of advantages over almost
> all
> other PICs for learning:
> - Each pin only does one thing
> - All the RAM is echoed in all banks
>
> For a lot of people, learning any microcontroller is kind of intimidating.
> With only 35 instructions, the PIC16 isn't rocket science to be sure, but
> many of people approach it with a lot of uncertainty. While the step up
> from the 84 to anything else isn't a big one once you have your head
> around
> the PIC, trying to learn the PIC while your variables disappear every time
> you do the mysterious banksel to access a register, and remembering to
> turn
> off peripherals you don't yet understand makes it a lot harder for the
> newbie.
>
> Once you know what you are doing, these things are, at worst, minor
> irritations, but when you first approach the PIC, they add to a barrier
> that
> already appears to be a lot higher than it is.
>
[snip]

> That being said, I wonder if the newbie in this day and age shouldn't be
> heading right for the 18F anyway. No banking, a lot of the 16F
> irritations
> are gone, and prices have reached the point where it is hard to tell the
> difference. There is no 84 equivalent so you need learn to turn off the
> analogs right away, but there is none of that annoying banking, and most
> of
> the quirky instructions have been fixed. The main thing lacking is
> example
> projects.

Code page banking is gone with the 18F parts, but memory banking is
still there (darn it!) - Then there is the access page and the linker
files. Hmm, maybe the 18F isn't the place to start.

DLC
> 72/73 de WB8RCR http://www.qsl.net/wb8rcr
> didileydadidah QRP-L #1446 Code Warriors #35
> ------------------------------------
>
> to unsubscribe, go to http://www.yahoogroups.com and follow the
> instructions



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> Code page banking is gone with the 18F parts, but memory banking is
> still there (darn it!) - Then there is the access page and the linker
> files. Hmm, maybe the 18F isn't the place to start.
>

The 16F874 is a nice part. It has a lot of the cadillac features but is still
the PIC16 architecture. You can also get new ones cheap.

I had a hard time with linker scripts. They're not documented very well and
they're really intended for the C compiler. I do not recommend that a beginner
try to work with the C compiler. It's complicated. You really need some
experience with the parts before you start working with it.

Mike Harpe

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