[UART] GPS 18-5Hz LVC and COM1 silence, OK on Linux though...

Kevin Oberman rkoberman at gmail.com
Sun Apr 28 23:04:06 UTC 2013

On Sun, Apr 28, 2013 at 3:41 PM, Igor Mozolevsky <igor at hybrid-lab.co.uk>wrote:

> On 28 April 2013 13:48, Igor Mozolevsky <igor at hybrid-lab.co.uk> wrote:
> <snip>
> > # cu -l /dev/cuau0 -s 4800
> > Connected
> >
> > and after the 'Connected' there is just silence (should be getting
> > $GPGLL every 200ms from the GPS unit)...
> > Obviously I'm missing something, just can't figure out what it is...
> I should add that when I connect through uplcom on cuaU0, the messages
> come through (and ntpd can use them) but I need the UART connection
> for the PPS sync...
> --
> Igor M.


Even though you have only a single physical port, most systems have at
least a dual serial UART controller, though only one mat have a DB-9
connector attached. Can you look at /var/run/dmesg.boot and confirm that
only one UART is is found? E.g.:
uart0: <16550 or compatible> port 0x3f8-0x3ff irq 4 flags 0x10 on acpi0
uart1: <16550 or compatible> port 0x2f8-0x2ff irq 3 on acpi0
(Note that this system has only a single DB-9 connector for uart0. I
suspect that there is a header for uart1 on the board, but I've never had a
need to check.
R. Kevin Oberman, Network Engineer
E-mail: rkoberman at gmail.com

More information about the freebsd-stable mailing list