Parts website recommends PIC-PG3

At the Houston meeting on Sunday, topic came up that the official parts.reprap.org suggests the PIC-PG3. This requires a computer parallel port... which many systems don't even have any more.

One RepRapper had programmed his parts with the serial (rs232) PIC-PG2. Since the RepRap already requires a serial rs232 interface... seems logical to switch the official recommendation.

Plus the PIC-PG2 is cheaper on the Microcontrollershop.com (suggested Reprap vendor). $16 vs. $25.

Zach, any reason to not change this?

Edited 2 time(s). Last edit at 01/03/2008 02:19PM by RoundSparrow.

because the PIC-PG2 requires a serial port that is in-spec. the problem is that many serial ports are not in-spec and the PIC-PG2 is very unreliable. the PIC-PG3 has an external power supply and works every time.

if the PIC-PG2 works for you, go for it!

ZachHoeken Wrote:
-------------------------------------------------------
> because the PIC-PG2 requires a serial port that is
> in-spec. the problem is that many serial ports
> are not in-spec and the PIC-PG2 is very
> unreliable. the PIC-PG3 has an external power
> supply and works every time.
>
> if the PIC-PG2 works for you, go for it!


Ok, let's try this from another perspective: Doesn't your shopping list also specify an exact USB->rs232 converter - is that particular one 'in spec'? In other words... with a known usb->rs232 converter, the PIC-PG2 would work?

BTW, not all printer ports are in spec At least on my I had to change the mode in my BIOS from bi-direction to ECP to get it to work with the PIC-PG3.

That's interesting. I didn't even know the serial ports had different specs. I haven't had any problems with my PG2. (the one Sparrow is talking about) and I've been programming 16F and 18F.

If it has been problematic for people, then it might not work too well. On the other hand, it's the only programmer I've ever had and it's been fine.

This might not be too much of an issue in the long term if the Arduino is eventually going to take over. I personally like the PIC system because you can design your boards almost any way you like and just throw in the chip. With the arduino it looks like you need a seperate board just for that.
That's just my pref though.

Dylan

The ardunio is just a breakout board for a ATmega168. You could do the same thing for the PIC and have one control all the other boards. Or you could put ATmega168s on all the boards instead of pics. Lots of ways to do it. I mostly work with PICs (the new pic32s look sweet!), but the ardunio is very nice, I like not needing a ICD2 to communicate with it. plus if you read makezine there are lots of cool projects that use it, so its got support and easy to use :-)

Originally, I think the Reprap wiki suggested a PG2. That changed just around
the time I bought one! This was back before the parts website existed.

I have a PIC-PG2. It works for me ... on just *one* PC out of about 4 or 5
I have connected it to! So this "serial port compatibility" thing is a real
issue -- your serial port *has* to provide something close to 12V, basically,
even though most "normal" devices people connect to serial ports will work
fine with the signal levels at 9V or in some cases 5V. The PIC-PG2 needs
the full 12V to be able to do its job, as far as I know.

Further, the PIC-PG2 will *not* work over a USB-to-Serial converter at all,
possibly because it drives the control signal lines in unorthodox ways
that such converters cannot emulate.

On the plus side, both the PIC-PG2 and PIC-PG3 use pinouts to the PC that
are "well-known" and so are supported by various free and open source PIC
programming software. If you get a USB-based PIC programmer, you may end
up stuck with using only the (Windows-based) software that comes with it.
This will matter more to some people that to others, but is worth bearing
in mind.

So, as I see it, the current reasonable choices are:

(a) A PIC-PG2: Very inexpensive (under US$15), but needs a real serial
port that delivers 12V. Whether it works with *your* serial port is
basically a gamble. I have access to enough older PCs to make
it worthwhile to me to take that risk. Not everyone does.

(b) A PIC-PG3: $10 or so more than the PIC-PG2, needs a parallel port.

(c) Other programmers that have an external power supply, some of which
are USB-driven. These are usually more expensive, though.

(d) An official ICD-2 (US$160) or a PICSTART-Plus (US$199). Expensive,
but very well supported, can use the Microchip MPLAB IDE, etc.
I don't recommend this, unless there is some special reason why you
need it unrelated to the Reprap project -- it's too much money :-)

Of course, there is also the ultimate cheap method:

(e) Ask another Reprapper to program your PICs for you!

which may be entirely feasible, especially if you are more of a Reprap
"user" than a "developer" who will forever want to be hacking on the
firmware and trying new things. Maybe this is something that Reprap User
Groups could help with?

Jonathan

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Jonathan

Ok, I'm convinced there is no clear choice. I'm now fully educated on the issue

Yeah, I ran into the no-parallel-port problem a while ago. My current PC (Dell) has no built-in parallel port. I do have an older PC with one but it's inside and arcade cabinet.

I bought the PG3, realized my mistake, ordered a PG2 and used the PG3 attached to my arcade machine until the PG2 showed up.

I'm currently using COM1 on the Dell for both the PG2 and the RepRap. It's easy enough to connect and disconnect as needed. Both seem to run just fine on the end of the 6' cable running between my desk and workbench.