[PLUG] serial communication with dmm (was com port in guest to usb in host (virtual box))

[Russell Senior]

Have you measured the voltages on DTR and RTS during the runs?

Try it with sigrok and with the vendor software and see if there is a
difference in those values.

On Thu, Dec 28, 2017 at 9:51 PM, Denis Heidtmann
<denis.heidtmann at gmail.com> wrote:
> This saga continues.
>
> On the laptop with a usb-serial adapter I got to the point where the
> commands:
> sigrok-cli --driver mastech-mas345:conn=/dev/ttyUSB0 --show
> sigrok-cli --driver mastech-mas345:conn=/dev/ttyUSB0 --scan
> sigrok-cli --driver mastech-mas345:conn=/dev/ttyUSB0 --samples 10
>
> behave as expected except the last one returns no data.  I was advised to
> try using these same commands on the desktop which has an RS232 port, thus
> removing the usb-serial adapter from the picture.  Good idea.
>
> After just guessing what serial port to use, I run the following command:
>
> sigrok-cli --driver mastech-mas345:conn=/dev/ttyS0 --scan
> The following devices were found:
> mastech-mas345 - MASTECH MAS345 with 1 channel: P1
>
> This is the same response I got on the laptop.
>
> sigrok-cli --driver mastech-mas345:conn=/dev/ttyS0 --show
> mastech-mas345 - MASTECH MAS345 with 1 channel: P1
> Supported driver options:
>     conn
>     serialcomm
> Supported configuration options:
>
> This is the same response I got on the laptop.
>
> sigrok-cli --driver mastech-mas345:conn=/dev/ttyS0 --samples 10
>
> [no response except the usual ~10 second delay]
>
> This is the same response I got on the laptop.  RATS!
>
> This eliminates the usb-serial device from the picture.
>
> Recall that when running --samples 10 command on the laptop I was able to
> detect pulses on the serial line consistent (in a general sense) with a
> response from the dmm.  Also recall that running  the mfg. sw under windows
> on the desktop showed flawless communication.
>
> finally, I report:
> stty -F /dev/ttyS0 -a   speed 600 baud; rows 0; columns 0; line = 0;
> intr = <undef>; quit = <undef>; erase = <undef>; kill = <undef>; eof =
> <undef>;
> eol = <undef>; eol2 = <undef>; swtch = <undef>; start = <undef>; stop =
> <undef>;
> susp = <undef>; rprnt = <undef>; werase = <undef>; lnext = <undef>;
> discard = <undef>; min = 0; 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
>
> And the protocol is reported to be:
>
> data format: 7n2 at 600 baud (7 bits, no parity, 2 stop bits).
> Control lines:
>    DTR and RTS lines are used to power the TX line: RTS is clear
>    for -12 supply; DTR is set for +12 supply. Data transmission is
>    solicited sending whatever character to the RX line.
>
> Any suggestions as to where to go from here?
>
> Thanks,
> -Denis
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