Fundamental C question about "if" statements

On 2015-09-21, Tim Wescott <tim@seemywebsite.com> wrote:
>
> There are some Cortex-M0 parts showing up in PDIP, and there are Cortex-M0 
> parts with USB.  I don't know if the two sets intersect, however.
>

They don't unfortunately. It's something I keep a lookout for and I have
yet to come across such parts.

> With the exception of packages that have pads underneath (damn, what's 
> the name?), hand-soldering surface-mount assemblies just takes a steady 
> hand and a decent microscope.  And, I suspect one could make a good-
> enough microscope with the right web-cam and a 'puter.  So I don't see 
> why surface-mount and hobbyist should be mutually exclusive.
>

For some hobbyists (especially when you are doing high-end stuff) they
are not exclusive, but being able to breadboard a circuit makes the cost
of experimenting _very_ low (or even zero) and you don't have to pay for,
and wait for, the latest version of your PCB to be delivered through the
post.

And when you are ready to make your final circuit permanent, it's easy
enough to do so yourself without needing chemicals in the house.

Simon.

-- 
Simon Clubley, clubley@remove_me.eisner.decus.org-Earth.UFP
Microsoft: Bringing you 1980s technology to a 21st century world

Simon Clubley <clubley@remove_me.eisner.decus.org-Earth.UFP> writes:
>> There are some Cortex-M0 parts showing up in PDIP, and there are Cortex-M0 
>> parts with USB.  I don't know if the two sets intersect, however.
> They don't unfortunately. It's something I keep a lookout for and I have
> yet to come across such parts.

For prototyping and low quantity stuff you could possibly use a breakout
board, e.g.:

  http://www.pjrc.com/store/teensylc_pins.html

Op 21-Sep-15 om 8:23 PM schreef Simon Clubley:
> On 2015-09-21, Tim Wescott <tim@seemywebsite.com> wrote:
>>
>> There are some Cortex-M0 parts showing up in PDIP, and there are Cortex-M0
>> parts with USB.  I don't know if the two sets intersect, however.

I know of only two dip ARM chips: lpc810 (dip8, Cortex-M0+) and lpc1114 
(dip28, cortex-M0).

The lpc810 used to be priced nice (< $1 IIRC), but recenty they are 
priced much higher (~ $3). Anyobe know why??

Wouter

Wouter van Ooijen <wouter@voti.nl> writes:

> Op 21-Sep-15 om 8:23 PM schreef Simon Clubley:
>> On 2015-09-21, Tim Wescott <tim@seemywebsite.com> wrote:
>>>
>>> There are some Cortex-M0 parts showing up in PDIP, and there are Cortex-M0
>>> parts with USB.  I don't know if the two sets intersect, however.
>
> I know of only two dip ARM chips: lpc810 (dip8, Cortex-M0+) and
> lpc1114 (dip28, cortex-M0).
>
> The lpc810 used to be priced nice (< $1 IIRC), but recenty they are
> priced much higher (~ $3). Anyobe know why??

Only hobbyists buy them?

>
> Wouter
>

-- 

John Devereux

On Mon, 21 Sep 2015 22:00:37 +0200, Wouter van Ooijen wrote:

> Op 21-Sep-15 om 8:23 PM schreef Simon Clubley:
>> On 2015-09-21, Tim Wescott <tim@seemywebsite.com> wrote:
>>>
>>> There are some Cortex-M0 parts showing up in PDIP, and there are
>>> Cortex-M0 parts with USB.  I don't know if the two sets intersect,
>>> however.
> 
> I know of only two dip ARM chips: lpc810 (dip8, Cortex-M0+) and lpc1114
> (dip28, cortex-M0).
> 
> The lpc810 used to be priced nice (< $1 IIRC), but recenty they are
> priced much higher (~ $3). Anyobe know why??

My cynical genius is whispering that it's because they've gotten some 
design wins and now they want to cash in...

-- 

Tim Wescott
Wescott Design Services
http://www.wescottdesign.com

On Mon, 21 Sep 2015 10:06:47 +0200, David Brown
<david.brown@hesbynett.no> wrote:

>For students of computing history, it is interesting to look at K&R C to
>see why modern C is better.  But for people wanting to learn C for real
>use, it's about as much use as teaching medical students about
>blood-letting and prayers to Isis and Osiris before discussing antibiotics.

Umm ... modern medical students ARE taught about blood letting and
other things.  Leeches are used routinely after certain types of
surgery to control swelling, and maggots are used to remove dying and
dead tissue from wounds, which helps them heal.

And you have the wrong gods: modern doctors pray to themselves.
<grin>

George

Am 21.09.2015 um 20:11 schrieb Simon Clubley:
> On 2015-09-21, John Temples <usenet@xargs-spam.com> wrote:

>> The PIC24 is a completely new-from-scratch core that has nothing
>> whatsoever do with the PIC18.

> Yes, it has a new instruction set, etc, but it was advertised by Microchip
> as effectively an extension of the PIC18.

And being engineers we of course take all advertising statements 100% 
exactly at face value.  Sure.  No doubt about that.  None at all.  Yeah, 
right.

On Mon, 21 Sep 2015 14:03:14 -0400, Walter Banks wrote:

> On 20/09/2015 7:29 PM, Tim Wescott wrote:
>  >
>  >>> This is spelled out very well in "C, A Reference Manual" by
>  >>> Harbison and Steele.  There are other books out there (K & R comes
>  >>> to mind), and Harbison and Steele may not even be the best -- but I
>  >>> find that Harbison and Steele is a very good book for my purposes.
>  >>
>  >> I am looking at the C standards here (C11, document N1570).
>  >>
>  >>
> A few posts ago you mentioned "C, A Reference Manual" by Harbison and
> Steele. This is a very good "readable" reference on C that has been
> periodically updated. The authors are remarkably approachable and the
> book is high on my short list of essential references.
> 
> 
> w..

I'm glad that there are others out there that share my enthusiasm for the 
book.  It's been a while since I've just read it cover-to-cover, but it 
does an excellent job both as the reference manual it claims to be (99% 
of my usage of it these days starts with the index) and as a text that 
can be read from page 1 on to the end.

-- 
www.wescottdesign.com

On 21/09/15 19:24, Tim Wescott wrote:

> But it is a point -- who IS the Egyptian god of computing?
> 

I don't know that one - but some candidates could be:

Am-heh – A dangerous underworld god
Apep – A serpent deity who personified malevolent chaos
Heka – Personification of magic

(I justify including Heka on the list from what customers expect of us.)

When I develop my own programming language to be the perfect replacement
for C and all it's quirks, I shall call it Apep.


If one were looking for interesting problems to practice writing C code
(though not for embedded systems), I'm sure ancient Egyptian fractions
could inspire some good challenges:

<https://en.wikipedia.org/wiki/Egyptian_fraction>

On 22/09/15 00:24, George Neuner wrote:
> On Mon, 21 Sep 2015 10:06:47 +0200, David Brown
> <david.brown@hesbynett.no> wrote:
> 
>> For students of computing history, it is interesting to look at K&R C to
>> see why modern C is better.  But for people wanting to learn C for real
>> use, it's about as much use as teaching medical students about
>> blood-letting and prayers to Isis and Osiris before discussing antibiotics.
> 
> Umm ... modern medical students ARE taught about blood letting and
> other things.  Leeches are used routinely after certain types of
> surgery to control swelling, and maggots are used to remove dying and
> dead tissue from wounds, which helps them heal.
> 

Yes, I happen to know that.  I am addicted to science and history
magazines - collecting (hopefully!) useless knowledge is a hobby.
However, medical students are not taught that blood letting is the cure
for /everything/, as medieval European doctors seemed to think.

> And you have the wrong gods: modern doctors pray to themselves.
> <grin>

:-)

> 
> George
>