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Vitaliy | 1 Mar 2010 05:02

Re: [EE] PCB etching experience

M.L. wrote:
> I had access to a machine several years ago in college. I was never
> able to get very good boards with it. Milling the PCB results in
> grooves on the surface which makes a rough and unsightly board. There
> is no solder mask or silkscreen. Unless the bit is brand new it will
> do a poor job milling the copper, leaving burrs that will short out
> traces. IIRC the minimum trace/space with this machine was 10mil/10mil
> (0.01 inch) which precludes any modern parts. You can do two layer
> boards but you can't do plated through vias or holes.
>
> All-in-all it's a bum deal for a machine that is (at minimum) several
> thousand dollars. It hasn't really caught on because people who have
> the capital to pay for it are probably willing to pay to have boards
> expedited, and are probably also doing "state-of-1970" circuit boards
> that are too advanced for a milling machine to produce.

We looked at CNC for prototype production, but as you say it did not look 
like it was going to be cost effective. It would take years for the machine 
to pay for itself (compared to getting the protos from a board house), and 
you don't get a "production quality" PCB.

Vitaliy 

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Jason Hsu | 1 Mar 2010 05:47
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Re: [PIC]Function declaration causes error in one program but not another

I still haven't had any luck figuring out what was causing my problem.

I have uploaded my code (an older version that had this problem) to
http://www.jasonhsu.com/swrwatt_2010_0224_2131.c .  The code as is
will compile.  Uncommenting the delay_1_msec declaration will cause
the error to show up.

I agree that I need to figure out why I was getting these cryptic
function declaration errors even though the same offending lines
(verbatim) had no such effect in another program.  As a student and as
an engineer, I have found all too often that political pressure has
encouraged me to just get the job done rather than take the time to
understand just what I'm doing.  Since I don't have a professor or
boss breathing down my neck over this matter, I cannot use this as an
excuse to pass up this learning opportunity.
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William "Chops" Westfield | 1 Mar 2010 05:52
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Re: [EE] PCB etching experience


On Feb 28, 2010, at 10:07 AM, Peter Restall wrote:

> Has anybody got any practical experience of CNC-ing prototype boards ?

Here's a copy of the message I sent out several years ago...

> I bought a used LPKF from eBay a couple years ago for hobbyist
> usage.  Less than half the price of the cheapest new unit...
>
> I don't know if it was worth it.  I'm pretty sure I'm still far
> behind where I'd be $-wise if I'd sent every board I've made
> (including the N iterations of some of them) to a professional
> fabricator.  It's nice to be able to go from eagle design to
> SS PCB in a couple hours, especially for the tiny boards that
> aren't quite right that I tend to make, but often the several
> hours of baby-sitting needed don't come along for quite a while,
> and I could've sent them out.
>
> It's a pain not having Plated through holes.  Yeah, the newer
> systems have some PTH system of somesort, but it adds to the
> time and complexity of fabrication...
>
> It's a pain not having a soldermask.
>
> Tools and other expendable items are expensive; you can buy surplus
> partially used drills for cheap, but the mechanical etching bits are
> uncommon, without many providers, and rather expensive (and they
> wear out pretty quick.)
>
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Alex Harford | 1 Mar 2010 06:11
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Re: [PIC]Function declaration causes error in one program but not another

Jason, the strange thing I see is that the newlines are odd looking.
See what it looks like opened on a Linux box in vim:

http://imgur.com/qvgwj

There are ^Ms shown, but where you pasted the code in, there is a ^M
but it didn't cause a newline!?

Maybe a dos2unix / unix2dos pass will straighten things out.

On Sun, Feb 28, 2010 at 8:47 PM, Jason Hsu <jhsu802701@...> wrote:
> I still haven't had any luck figuring out what was causing my problem.
>
> I have uploaded my code (an older version that had this problem) to
> http://www.jasonhsu.com/swrwatt_2010_0224_2131.c .  The code as is
> will compile.  Uncommenting the delay_1_msec declaration will cause
> the error to show up.

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Jason Hsu | 1 Mar 2010 06:16
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Re: [PIC]Function declaration causes error in one program but not another

Please use MPLAB to view my code.  That's what I used to create it.

On Sun, Feb 28, 2010 at 11:11 PM, Alex Harford <harford@...> wrote:
> Jason, the strange thing I see is that the newlines are odd looking.
> See what it looks like opened on a Linux box in vim:
>
> http://imgur.com/qvgwj
>
> There are ^Ms shown, but where you pasted the code in, there is a ^M
> but it didn't cause a newline!?
>
> Maybe a dos2unix / unix2dos pass will straighten things out.
>

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Alex Harford | 1 Mar 2010 06:22
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Re: [PIC]Function declaration causes error in one program but not another

I know, but there is something funny going on.  I looked at it with
'xxd' and you have a CR/^M/0x0D with no LF/0x0A, and I will bet that's
confusing the compiler.

I'm willing to bet if you took these lines out:

// This method of providing delays isn't efficient with respect to
clock cycles.  It takes 9 usec to decrement a variable.  However, it
does work.^M// Purists advocate inserting Assembly language into the
code.  My attempts to implement this were not successful.
// Executing delay_1_msec 1000 times takes about 1 sec.^M//void
delay_1_msec (void)

and retyped

void delay_1_msec (void)

with the remaining part of the function uncommented, it would work.

On Sun, Feb 28, 2010 at 9:16 PM, Jason Hsu <jhsu802701@...> wrote:
> Please use MPLAB to view my code.  That's what I used to create it.
>
> On Sun, Feb 28, 2010 at 11:11 PM, Alex Harford <harford@...> wrote:
>> Jason, the strange thing I see is that the newlines are odd looking.
>> See what it looks like opened on a Linux box in vim:
>>
>> http://imgur.com/qvgwj
>>
>> There are ^Ms shown, but where you pasted the code in, there is a ^M
>> but it didn't cause a newline!?
(Continue reading)

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Russell McMahon | 1 Mar 2010 07:22
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Re: [PIC]Function declaration causes error in one program but not another

> Please use MPLAB to view my code.  That's what I used to create it.

But, the compiler doesn't care WHAT you created it with OR what someone
viewed it with, it just cares about what's in the file.

It's looking strongly, based on various prior posts, and on Alex's last two,
that the file has content which is interpreted by various things in various
ways and, importantly, the compiler appears to see something that MPLab+your
eyes+ your brain can't see.

It sounds like your system has provided you with an immensely valuable
embedded (and other) programming learning experience :-).

Suggestion:

Try typing in the 'identical" code as you see it after cut and pasting and
then delete the cut and pasted code and see if it compiles OK. If so, THEN
go back and hunt it down and kill it. You then can chalk another "mission
flown" symbol on the side of your cockpit.

   Russell

(Lancaster "G for George", which rests in the brightly lit darkness of the
Canberra National War Memorial Museum in Canberra Australia has (AFAIR)
about 100 mission-flown symbols on the side of its cockpit. Each one denotes
a safely survived wartime mission. Statistically, the odd aircraft has to
manage this sort of result - but happy indeed the crew that get to fly in
it. You'll be a few mission symbols short of that so far I suspect. After
you find your bug you can paint on another one and look forward to the day
that you've achieved 120 missions equivalent :-)).
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Dario Greggio | 1 Mar 2010 09:26
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Re: [PIC]Function declaration causes error in one program but not another

Alex Harford ha scritto:
> I know, but there is something funny going on.  I looked at it with
> 'xxd' and you have a CR/^M/0x0D with no LF/0x0A, and I will bet that's
> confusing the compiler.

same here, opening with MSVC's editor
so I'm almost sure it causes problems.

I can save it and send you back the file if you want..

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cdb | 1 Mar 2010 09:35
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Re: [PIC]Function declaration causes error in one programbutnotanother


<snip>
:: and similarly a = a + 1 than a++.
</snip>

Strangely enough I have a 'C' compiler that will actually provide 
different assembler for 

a = a +1

to

a+= 1

One uses movlw and goes through all sorts of contortions and'ing and 
or'ing all over the place - the other   inc a .

It even gives different results depending on whether it is part of a 
While or For loop.

Colin
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Dario Greggio | 1 Mar 2010 09:34
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Re: [PIC]Function declaration causes error in one program but not another

http://cyberdyne.homeip.net/public/swrwatt_2010_0224_2131.c

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