Re: belkin usb serial converter (mct_u232), break not working

[Paul Fulghum]

Thomas Stewart wrote:

> I've tyred various combinations of ioctl(fd, TCSBRKP, x) and tcsendbreak(fd, 
> x), where x is 2, 5, 10, 20 and 200.
>
> One thing I did notice is that no mater what the value I use, it always 
> finishes very quickly, there does not appear to be any duration.
>
> take porttest.c:
> #include <sys/fcntl.h>
> #include <sys/ioctl.h>
> main(int argc, char ** argv) {
>        int fd = open(argv[1], O_RDWR|O_NOCTTY);
>        ioctl(fd, TCSBRKP, 20);
>        close(fd);
> }
>
> $ time ./porttest /dev/ttyS0
> real    0m2.001s
> user    0m0.001s
> sys     0m0.000s
>
> A standard serial port with a 2 second break (20*100ms), takes as expected 
> just over 2 seconds.
>
> $ time ./porttest /dev/ttyUSB1
> real    0m0.004s
> user    0m0.000s
> sys     0m0.001s
>
> However with the USB converter instead, it takes 5 ms to complete. Much 
> shorter than expected.
>
> Is it a driver issue?
>  
Could be.
That test gives me more information.
I will look closer at the code and see if anything pops out.

Thanks,
Paul

--
Paul Fulghum
paulkf@xxxxxxxxxxxxx


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