#7 intrupt v polling

[Anonymous]

Is there a way to use interrupts when the input pins
change, or is polling my only option?

Polling seems to take a lot of cpu cycles.
I've been able to slow it down with time.sleep()
but I miss inputs.

Can interrupts be added?

[Nobody/Anonymous]

Logged In: NO

sorry this ? is for the pyparallel

[Matthias Blaicher]

Logged In: YES
user_id=947280
Originator: NO

I'm also interested in this - mainly Event on RX. Isn't there any nice way of doing so? I hate bruning CPU cicles by waiting.

I'm using Linux - so maybe there is an OS specific implementation?

[altraqua]

This a solution using TIOCMIWAIT syscall.
Not all USB adapter supporti this feature.
It should be integrated in pyserial.

---

from serial import Serial
from fcntl import ioctl
from termios import (
TIOCMIWAIT,
TIOCM_RNG,
TIOCM_DSR,
TIOCM_CD,
TIOCM_CTS
)

ser = Serial('/dev/ttyUSB0')

wait_signals = (TIOCM_RNG |
TIOCM_DSR |
TIOCM_CD |
TIOCM_CTS)

if __name__ == '__main__':
while True:
ioctl(ser.fd, TIOCMIWAIT, wait_signals)
print 'RI=%-5s - DSR=%-5s - CD=%-5s - CTS=%-5s' % (
ser.getRI(),
ser.getDSR(),
ser.getCD(),
ser.getCTS(),
)