[Robotgroup] USB to parallel problems

[Robo Al]

I do agree with you on the added level of complexity, there's
no doubt that the parallel port is easier. But I think you
may have had bad experiences in the past with USB that make
you think it is hard. New offerings are easy to work with (or
at least I think they are easy, and I am not a genius ;-)

The PIC18F2450 is $2.81 (qty. 25 from mouser). It comes with
the standard CDC drivers that means it looks like a serial
port.

It did take me a few days to figure out the basics for creating
my own firmware. I can get a new interface developed within a
single day that works both on windows and linux.

Seriously, buy a UBW from Sparkfun, give it a chance and look at
the firmware (and how you can adapt it to your needs). From what I
know from you, I can tell you that you'll get it to work in no time
and within a day you'll be writing your own firmware to do anything
you want.

Send me a reminder on Wednesday and I'll bring mine along and show
you a simple example next meeting. I showed it while we were meeting
at Poke's so it was before you joined the group.

Alberto

On Sun, 2008-04-20 at 00:10 -0500, Andre Lamothe wrote:
> I agree on a practical level with you, but...
> 
> The problem with USB though is that its not trivial to design, the protocal 
> is worst than ethernet, and the chips are VERY expensive. But, I agree on 
> new products you have to go USB. But, 99% of most dev tools in EDA, etc. 
> still have parallel programmer drivers, so you need parallel ports. You 
> "can" get a USB version, but they are closed protocals's usually and the 
> engineering time to develop a programmer based on the protocal is literally 
> 25-50x more than the parallel port. So I agree, everything should go USB, 
> but USB is overly complex at best for getting simple I/O to work. You have 
> to be a pretty sophisticated engineer to write a USB driver and implement 
> both sides of the hardware, that's all I am saying. With parallel, two mins 
> your done, with serials, 2 days you're done with USB 2 months you are done 
> :)
> 
> Its just a bad situation that these legacy ports are slowly going bye bye, 
> because it REALLY does make a lot of things harder. for example, a simple 
> set of switches that I might want to interface to the PC, I can do that with 
> the parallel port, or at worst with a PIC and the serial port (which still 
> works thank god). But, if I have to interface to USB, it can be done with a 
> Pic in software for $2-3, but it's a LOT of work. So the problem I see is 
> that the ROI on your engineering effort is really low when you have to use 
> USB for simple interfaces.
> 
> Andre'
> 
> ----- Original Message ----- 
> From: "Robo Al" <sp-18561884 at ggsys.net>
> To: "The Robot Group Mailing List" <robotgroup at puremagic.com>
> Sent: Saturday, April 19, 2008 11:42 PM
> Subject: Re: [Robotgroup] USB to parallel problems
> 
> 
> Actually for just bit banging I would no longer recommend the
> parallel port (basically due to the problems you are encountering)
> 
> I have been very happy with the UBW (usb bit wacker)
> http://greta.dhs.org/UBW/ which is what I would use if I didn't
> want to deal with electronics soldering (can be bought for $25
> fully assembled) or programming (comes pre-configured and is controlled
> with any terminal program).
> 
> For advanced control, you can use the same hardware with your own
> firmware (comes with a bootloader so you upgrade the firmware without
> having any special programmer)
> 
> All and all the parallel port is great and I've used it to do a
> few things, but it is dying. Even if you find it in a motherboard
> it is likely not using hefty drivers, but rather the cheap stuff
> that can't drive some of the peripherals. I spent 2 weeks trying to
> figure out why my brand new CNC motor controller wouldn't work and
> it turned out that both systems I was using used too cheap parallel
> port implementations not able to drive the logic chips in the
> controller. Found an old computer and everything started to work
> perfectly.
> 
> I can understand your need for something that will talk to your
> already existing products, which I thought is your current problem.
> But if you are designing anything new I would stay away from parallel
> port implementations, USB is cheap and easy to implement nowadays.
> 
> My 2 cents,
> 
> Alberto
> 
> 
> On Sat, 2008-04-19 at 23:23 -0500, Andre Lamothe wrote:
> > Right, this particular product is made by someone that is on the fench 
> > with
> > if its commercial, etc. So I am concerned that he would change his mind at
> > some point, but the more pressing matter is the code base, etc. is the 
> > thing
> > I don't want to deal with. But, if I don't find anything and it becomes a
> > problem then it might be my only short term solution.
> >
> > However, haven;t got a single complaint yet except from a MAC latop user, 
> > so
> > I am starting not to worry and it might work itself out, however, I, me,
> > moi, would still like a USB to parallel from a real company that allows 
> > bit
> > banging. I mean everyone in the robot group I am sure would like to hook
> > things to the computer and turn on/off digital I/Os, the parallel port is
> > the only EASY way to do this. In 5 mins, I can be turning LEDs on with a
> > parallel port, and 10 lines of C code.
> >
> > Andre'
> 
> 
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