Well, just in case...I wired a switched connector. That found no communication: denis@denis-ThinkPad-L420:~$ sigrok-cli --driver mastech-mas345:conn=/dev/ttyUSB0 --samples 10 sr: serial: Didn't find a valid packet (read 0 bytes). No devices found.
For completeness, here are the interface conditions (in case you can see anything needing changing): denis@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 -Denis On Sat, Dec 16, 2017 at 4:10 PM, Russell Senior <russ...@personaltelco.net> wrote: > On Sat, Dec 16, 2017 at 3:48 PM, Denis Heidtmann > <denis.heidtm...@gmail.com> wrote: > > Yes, Russell, I thought of that. I first need to install the driver for > > the usb-serial device, recall how I did that on the laptop, and try to do > > it the same way. But I will pursue that when I get access to the > desktop. > > > > Is there a line on the usb that should be bouncing up and down when RXD > is > > bouncing? BTW, I notice that the designations rx/tx seem to switch > > depending on which instrument the terms are referred to. The schematic I > > have clearly shows that the designation RXD applies to the data line out > of > > the dmm. TXD is the line sending stuff into the dmm. I am assuming that > > this is OK since I clearly see 10 groups of pulses out of the dmm when I > > send the command --samples 10. > > Yeah, no one ever seems to specify what they mean by TX and RX, or at > least not in a way I comprehend. I have found the most reliable thing > is to just try it one way (almost at random), and if that doesn't > work, reverse and try again. Obviously TX on one side of a UART > should connect to RX on the other side. Some labelling seems to be to > "hey, connect TX here!" which suggests that it is RX. Or maybe the > reverse. Anyway, I have yet to damage anything perceptibly with the > try-swap-try dance. > _______________________________________________ > PLUG mailing list > PLUG@pdxlinux.org > http://lists.pdxlinux.org/mailman/listinfo/plug > _______________________________________________ PLUG mailing list PLUG@pdxlinux.org http://lists.pdxlinux.org/mailman/listinfo/plug
