Re: TTL/USB converter usage question

[RVP <rvp%SDF.ORG@localhost>]

On Wed, 16 Oct 2024, Ramiro Aceves wrote:

> netbsd-raspa4$ { sleep 1; stty -f /dev/ttyU0 9600 raw clocal cread
> -crtscts; } & cat -u -v /dev/ttyU0
> stty: /dev/ttyU0: Resource temporarily unavailable

Wrong device--use /dev/dtyU0.

OK, the only thing I can think of is that there's something which cu is
setting on the serial-port, but, which we're not: for example, there's
mdmbuf and cdtrcts which I haven't seen on Linux (but, -clocal should've
taken care of both of these..). Let's use the same settings cu uses:

1. Run your cu command:

$ cu ...

2. While cu's running, copy the settings:

$ stty -f /dev/dtyU0 -g > /tmp/cu-set.txt

3. Stop cu, run cat with saved cu settings:

$ { sleep 1; stty -f /dev/dtyU0 "$(cat /tmp/cu-set.txt)"; } & hexdump -C /dev/dtyU0

OR, using kre's method:

$ (stty "$(cat /tmp/cu-set.txt)"; hexdump -C) < /dev/dtyU0

and if the device is constantly spewing data at the serial port, you should
see it now.

-RVP

PS. you wrote:

> [...] and I can see all bytes returned by the GPS module when asked with the 
> @@Ea command by the PIC microcontroller.:

Does this mean that you have somehow to trigger the GPS module with a command
before it'll send data? If yes, and you're ending that command using cu, then
you'll have to do the same when using cat/hexdump. Otherwise, you'll just sit
there until the end of time (more realistically, until the power-supply goes off)
waiting for data which'll never come...