> Hi Joe,
>
> > After digging a bit further I found that the problem isn't lost
> characters or character corruption at all...
> >
> > The UART is actually at 460KBaud (not 900KBaud as I mentioned
> earlier).
> How did you verify that register read?
>
I actually looked at the setting applied in my code (which I should have done earlier, oops :p).
...
newtio.c_iflag = (IGNPAR);
newtio.c_oflag = 0;
newtio.c_cflag = B460800 | CS8 | CLOCAL | CREAD;
newtio.c_lflag = 0;
newtio.c_cc[VINTR] = 0; /* Ctrl-c */
newtio.c_cc[VQUIT] = 0; /* Ctrl-\ */
newtio.c_cc[VERASE] = 0; /* del */
newtio.c_cc[VKILL] = 0; /* @ */
newtio.c_cc[VEOF] = 0; /* Ctrl-d */
newtio.c_cc[VTIME] = 0; /* inter-character timer unused */
newtio.c_cc[VMIN] = 1; /* blocking read until 1 character arrives */
newtio.c_cc[VSWTC] = 0; /* '\0' */
newtio.c_cc[VSTART] = 0; /* Ctrl-q */
newtio.c_cc[VSTOP] = 0; /* Ctrl-s */
newtio.c_cc[VSUSP] = 0; /* Ctrl-z */
newtio.c_cc[VEOL] = 0; /* '\0' */
newtio.c_cc[VREPRINT] = 0; /* Ctrl-r */
newtio.c_cc[VDISCARD] = 0; /* Ctrl-u */
newtio.c_cc[VWERASE] = 0; /* Ctrl-w */
newtio.c_cc[VLNEXT] = 0; /* Ctrl-v */
newtio.c_cc[VEOL2] = 0; /* '\0' */
/* Clean the modem line and activate the settings for the port
*/
tcflush (handle->serialFD, TCIFLUSH);
tcsetattr (handle->serialFD, TCSANOW, &newtio);
...
I then loop read from a file descriptor to see the received bytes:
serialFD = open ("/dev/ttyO0", O_RDWR | O_NOCTTY);
...
while (1) {
count = read (serialFD, buffer, MAXIMUM_LINE_LENGTH);
...
debug here...
...
}
And it's by inspecting the bytes read that I noticed the inserted 0x00 on 3.3.
>
> The data received is very bursty (i.e. sets of messages every second
> or so), containing a
> > sync sequence to indicate a start of packet.
> >
> > The received bytes should be: 0x01, 0x52, 0x41 ....rest of packet.
> >
> > This works 100% of the time on 3.2, but on 3.3 I sometimes (but not
> always) get: 0x01, 0x00, 0x52, 0x41.
> >
> > i.e. there is a NULL/0x00 inserted after the first character.
> >
> > All this is tested using a very simple userspace application thats
> reads data from ttyO1.
> >
> > Any ideas? Should I kick open a new thread as it's not really to do
> with suspend anymore?
> Is there any flow control you are using?
No flow control, but lack of flow control hasn't caused problems up to 3.2.
Cheers,
Joe
>
> >
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