Write to MAC's serial port to talk to Arduino (fopen( /dev/tty.usbmodem1431) hangs forver)

Question

I have a problem with TTY device on MAC. I created a script which talks to Arduino and works well on Linux. Problem I'm having with MAC is I can't "fopen" the device. For example, if I do

echo "foo" > /dev/tty.usbmodem1431

It hangs forever blocking the port. It works well from Arduino's Serial Monitor so theoretically I should be able talking to it.

OK. I found the solution. I have to write to

/dev/cu.usbmodem1431

I still don't know why TTY don't want to work.

I'm not sure I understand question. I use "/dev/tty.usbmodem1431" — Lukasz Kujawa, Feb 20 '13 at 11:13
Which Arduino Board are you using. You might be using the wrong port. See here for more info. http://arduino.cc/en/Guide/MacOSX#toc8 — blarg, Feb 20 '13 at 11:15
I use correct port which is the one I posted in my question. I believe it's the correct one because it works well from the Arduino IDE. — Lukasz Kujawa, Feb 20 '13 at 11:24
See: http://stackoverflow.com/questions/8632586/macos-whats-the-difference-between-dev-tty-and-dev-cu for why cu works when tty does not. — Dave X, Feb 05 '14 at 20:03

score 2 · Answer 1 · answered Jun 08 '13 at 18:35

You can use tty with:

stty -f /dev/tty.usbmodem1431 cs8 115200 ignbrk -brkint -icrnl -imaxbel -opost -onlcr -isig -icanon -iexten -echo -echoe -echok -echoctl -echoke noflsh -ixon -crtscts

echo "hello" > /dev/tty.usbmodem1431

Where 115200 is your Serial.begin speed.

score 1 · Answer 2 · answered Jan 09 '14 at 04:13

1

What speed are you using? The default speed of Max OSX is 9600. Give it a try (when you set serial in your arduino program). stty does not seem to change the speed as one would expect.

answered Jan 09 '14 at 04:13

user1139880

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Write to MAC's serial port to talk to Arduino (fopen( /dev/tty.usbmodem1431) hangs forver)

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