> From: Chris Albertson [mailto:albertson.ch...@gmail.com]
> OK, then you likely don't need a FT232 chip. The microcontroller,
> whichever one you use, will likely have USB2 built-in. Or just make sure
> it does, so many chips have this.
> On Wed, Dec 2, 2020 at 12:00 PM <ken.stra...@gmail.com> wrote:
>
> > To clarify:
> > I am working on an accessory for a Tormach mill running PathPilot (a
> > flavour
> > of LinuxCNC). It is for personal use so I don't need to especially worry
> > about product cost but obviously I'd rather not spend a lot on something
> > that may eventually be abandoned when I get a better idea. I could modify
> > the Tormach source code to solve my timing problems but I'd prefer to use
> > it
> > unchanged to ease the installation of their updates.
It appears the issues isn't so much whether a processor with internal or
external USB is used. Even an internal one can be disabled so it won't be
enumerated by the PC OS.
The problem appears to be that the Arduino project takes longer to do what it
does on start-up than LinuxCNC does to send a couple of requests out the
USB/Serial port.
There are two problems as I see it.
1. If you wake up the USB too soon but don't listen to it then you miss the
messages and hang then waiting for them.
2. If you don't initialize the USB port then from LinuxCNC perspective the
device doesn't exist and it probably won't initialize or respond anymore.
Since I don't know exactly what Ken is expecting from the Tormach software it's
hard to give really good suggestions. I'd make opening the Serial Port for the
USB connection the highest priority operation in the Arduino project. Now at
least you can get the messages.
With this in mind what does the Tormach do if the USB is not plugged in. Then
after the Ardunio has powered up, done the motion control operations it needs
to do and is ready, you plug in the USB?
Does the Tormach then evaluate that there is now a serial port and send those
one or two messages?
Ie. First evaluate all the permutations on the Tormach side. You may find you
have no choice but to modify the Tormach. Or alternatively you lie to the
Tormach and tell it you are ready when you aren't. But then hold off on any
other commands from it until you are.
Of course if that means "Is the Tool changer out of the way so I can home?"
question may need an NO even if it is. Then a YES after the Arduino is done.
John Dammeyer
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