[PLUG] com port in guest to usb in host (virtual box)

[Denis Heidtmann]

Galen, thanks for the Clinic offer, but I will not be able to make it
there.

Since my last report I have set the baud rate and bits:

denis at denis-ThinkPad-L420:~$ stty -F/dev/ttyUSB0 -a
speed 600 baud; rows 0; columns 0; line = 0;
intr = ^C; quit = ^\; erase = ^?; kill = ^U; eof = ^D; eol = <undef>;
eol2 = <undef>; swtch = <undef>; start = ^Q; stop = ^S; susp = ^Z; rprnt =
^R;
werase = ^W; lnext = ^V; discard = ^O; min = 1; time = 0;
-parenb -parodd -cmspar cs7 hupcl -cstopb cread clocal -crtscts
-ignbrk -brkint -ignpar -parmrk -inpck -istrip -inlcr -igncr icrnl ixon
-ixoff
-iuclc -ixany -imaxbel -iutf8
opost -olcuc -ocrnl onlcr -onocr -onlret -ofill -ofdel nl0 cr0 tab0 bs0 vt0
ff0
isig icanon iexten echo echoe echok -echonl -noflsh -xcase -tostop -echoprt
echoctl echoke -flusho -extproc

What I do not seem to be able to set is "no parity".  I see odd and even
but not none in man stty.  The protocol is supposed to be:
data format: 7n2 at 600 baud (7 bits, no parity, 2 stop bits).


The narrowest pulse is 1.6ms except for a 0.8ms pulse at the start.  The
wide pulse is 5ms with a space of 3.3ms.






On Fri, Dec 15, 2017 at 11:36 AM, Galen Seitz <galens at seitzassoc.com> wrote:

> On 12/14/17 21:24, Denis Heidtmann wrote:
> > Measuring with a 'scope with the laptop issuing the  command sigrok-cli
> > --driver mastech-mas345:conn=/dev/ttyUSB0 --samples 10:
> >
> > triggering on DTR
> >
> > DTR goes from -6.6V to +7.6V and remains there 'till 9.64s
> > RX goes from -2.6V to +6.4V for .48s then again at 2.6s,3.12s, etc 'till
> > 7.32s (10 groups of data pulses after the initial .48s wide group)
> > RTS sits at -6.4V except for a narrow spike to +6.6V at 2.44s
> > TX  starts at -6.4V 'till 2.6s, 3.12s, etc where it has a double pulse of
> > 5ms each spaced 1.7ms. These pulse groups start synchronously with the RX
> > groups.
> >
> > If I want to get more detail I think I need to trigger on TX.
> >
> > So it looks like data is being sent. Is it received and sent to a bit
> > bucket, or not received by the usb-to-serial device?  How to find out?
>
> I think you should first confirm the baud rate.  Put your scope on the
> RX line (assuming that's the output from the DMM) and look for the
> narrowest positive or negative pulse.  That pulse width should tell you
> what baud rate the DMM is using.  Confirm that you have configured the
> serial port correctly.
>
> Do you have a digital scope?  If not, I can see how you might have
> trouble capturing these single shot events.  I could probably make it to
> the clinic on Sunday if you'd like some help with this.
>
> galen
> --
> Galen Seitz
> galens at seitzassoc.com
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