Improve target monitor and add target stty_params.

[doronbehar]

Use less as the default MONITOR_CMD. Change comment explanation about
# Serial Monitor.

Add stty_params target.

Make stty_params run a command according to Arch Linux's WiKi article on
Arduino #stty. Make monitor target depend on stty_params.

[sudar]

@doronbehar

Thanks for the PR.

Unfortunately I didn't get to it on time and it has resulted in some merge conflicts.

Can you please update your branch and fix the merge conflict?

[doronbehar]

Rebased against master.

[sej7278]

i'm also not sure what advantage less has over screen?

[wingunder]

i'm also not sure what advantage less has over screen?

I totally agree.

I have no problem to have less and cat as alternatives, but screen is currently the default and I vote for it to remain like that.

[doronbehar]

Personally, as for setting less as default, my opinion is that we should put defaults which are installed by default on almost every system. I can revert that if you really disagree with me..

[doronbehar]

In addition to less being installed on almost every machine by default, when using it just as a reader, one can send multiple characters commands to the port (in another terminal), as exampled in the echo command here: https://wiki.archlinux.org/index.php/Arduino#stty

[sudar]

@doronbehar

Changing the default monitor program will also break it for existing users. So I think it would be better to leave the default monitor program. Also if someone wants to change they can easily override the variable.

If you can remove the changes you made to set less as the default program and re-submit the PR, we could revisit it again.

[doronbehar]

Pushed a revert for your request.

[sudar]

@sej7278

What are your thoughts on the new stty_params target that is added?

[doronbehar]

Rebased again against master.

@sudar and @sej7278, I don't know how it goes on your machines but I use Arch Linux and when I run make monitor I sometimes get a bunch of gibberish characters and sometimes I get no output at all. With the stty_params target, I get a clear output just like I programmed.

[sej7278]

the arch arduino package is all sorts of broken so that doesn't surprise me, i've never had a problem on debian/fedora/osx. what's in your ~/.screenrc?

i don't like that stty_params is going to be called in all cases when running "make monitor" even for users without the problem, which could potentially introduce problems for them.

it seems this is changing arduino-mk to work around some sort of archlinux bug.

[doronbehar]

Thanks for your comment @sej7278, I might ask the Arch Linux community about the subject and inspect the way the arduino packages are built on other distributions.

I must say though, that I hardly believe there is an automated process that an OS can be configured to set these parameters by default whenever a new Arduino device is connected (perhaps using udev?), since there is an stty parameter defining the frequency of the communication between the two devices which is obviously different for every project..

Thinking about the frequency parameter, as a 1st idea, I was wondering, perhaps there is a default value being set by your OS's configuration that is identical to the one you are using in all of your Arduino projects? And that is why you never need to run any stty command on your machines?

Please leave this PR open for a while, I'll be glad to update you when you or my self will learn something new..

[sej7278]

i'd like to figure out what's going wrong with your setup so we'll keep the PR open to monitor (!) your updates.

when you mention setting frequency for different devices, you can either set $MONITOR_BAUDRATE, or it'll read it from Serial.begin() or defaults to 9600 8 N 1

that's not the sort of thing set in udev, that's traditionally for setting permissions for usbasp's or stlink/maple devices (generally add yourself to the dialout group and you're good to go).

[doronbehar]

I have made further tests and it seems the stty command is needed only when using cat, tail or less and not screen. I've found many suggestions around the internet for invoking a stty command:

• https://arduino.stackexchange.com/questions/19002/use-unix-terminal-instead-of-the-monitor-on-arduino-ide
• https://playground.arduino.cc/Interfacing/LinuxTTY
• https://arduino.stackexchange.com/questions/16776/how-to-connect-arduino-device-to-linux
• https://stackoverflow.com/questions/3918032/bash-serial-i-o-and-arduino

I think making the target stty_params a dependency of the target monitor should improve our safety anyway since printing unprintable characters in a terminal is known to be dangerous. I'm willing to add more commits that will make the monitor target run the stty_params target only when a MONITOR_CMD other then screen is used but I don't see any advantage in this.