**** BEGIN LOGGING AT Mon May 25 02:59:57 2020 May 25 03:02:12 so on a loop back on the UART if I send b'ok' and I get back \x00ce that is success? May 25 03:02:38 bbb uart txd -> max3232 T1IN, T1OUT -> device serial input, device serial output -> max3232 R1IN, R1OUT -> bbb uart rxd May 25 03:02:50 does it look like success to you? :P May 25 03:03:00 how are you testing? May 25 03:03:14 i just have a jumper going from Tx to Rx May 25 03:03:19 software I mean May 25 03:03:23 and I am in python May 25 03:03:33 so opened a serial port May 25 03:03:33 did you flush whatever garbage was still in the input buffer? May 25 03:03:40 yeah May 25 03:03:46 I am doing read(256) May 25 03:04:18 ok did it again May 25 03:04:27 and now I just get back b'ok' May 25 03:04:42 i.e. you somehow fucked up the first test or misinterpreted the results May 25 03:05:09 so you may want to examine why it gave a result that was different from what you expected May 25 03:05:20 (share a full transcript via pastebin if you can't figure that out) May 25 03:05:28 i think it is working May 25 03:05:34 i unplugged Rx May 25 03:05:42 and it gave me back x/00 May 25 03:05:51 \x00* May 25 03:06:12 it might do that if the pin has been configured to have internal pull-down May 25 03:06:38 (rather than pull-up) May 25 03:06:43 https://elinux.org/Beagleboard:BeagleBoneBlack_Debian#Debian_Buster_Console_Snapshot_for_BeagleBoard-xM May 25 03:06:52 This one does boot. May 25 03:06:54 Success. May 25 03:07:15 bufzi: yay May 25 03:07:35 so some of the crap installed on IoT images is causing problems May 25 03:07:52 is it normal behavior for all the unsent stuff to flow once the Rx is restored May 25 03:08:10 my next read after plugging the wire back into Rx i get a bunch of junk May 25 03:08:29 then it behaves alright May 25 03:08:33 MattB0ne: the junk is probably just the noise caused by making contact May 25 03:08:39 ok May 25 03:10:16 it's a bit weird for the uart rxd to have pull-down instead of pull-up, but once it's hooked up to something it won't really matter anymore May 25 03:10:44 (if it had pull-up configured then there wouldn't be any noise on the line when plugging in, hence no garbage received) May 25 03:11:20 easier to have erratic low signal near GND i assume? May 25 03:11:45 if I wanted to loop back after the MAX3232 I could just touch the wires right? May 25 03:12:22 no, the transmit line is driven high when idle so the rxd has pulldown and you connect it to something that's driving it high you'll get a signal transition, and since a connector doesn't make clean instantanous contact, you'll get garbage May 25 03:12:37 while if rxd is already high when you connect it to a txd that's also high, there's no signal transition May 25 03:13:01 *so when the rxd has pulldown and you connect it... etc May 25 03:13:38 for a loopback test you can just connect max3232 TOUT to RIN yes May 25 03:15:41 ok that works May 25 03:16:04 so need to read the manual on the device might need to switch modes or something May 25 03:16:16 also make sure you use the correct baudrate May 25 03:16:24 what device is this? May 25 03:16:30 yeah I have been keeping everything at 9600 May 25 03:17:01 https://www.flintec.com/electronics/digitising-units/em100 May 25 03:18:20 fancy May 25 03:19:53 supports rs485 too May 25 03:20:04 what does that buy you? May 25 03:20:38 better noise-immunity, supports longer wires, allows for ground-decoupling May 25 03:22:55 also allows multi-point communication across a shared bus (but the protocol used will need to ensure no two devices talk at the same time) May 25 03:24:16 what does full duplex vs half duplex mean for serial coms May 25 03:24:24 wondering if I need to change that May 25 03:24:37 Tx delay should be zero always? May 25 03:24:40 rs232 is always full-duplex May 25 03:24:53 it means you have separate wires for transmit and receive May 25 03:25:15 therefore you can transmit and receive independently and simultaneously May 25 03:25:50 half-duplex means a bidirectional connection is used and the two sides have to take turns in communication May 25 03:26:41 "tx delay" only applies to half-duplex communication, therefore is not relevant to you May 25 03:27:15 (and the factory default is 20ms according to the manual) May 25 03:28:25 hmmm gonna have to work on this tomorrow May 25 03:28:32 thing is not responding to me May 25 03:28:43 I have a USB to RS232 chord May 25 03:28:53 will try and bypass the BBB and MAX3232 May 25 03:28:58 see what the hell is going on May 25 03:29:07 sounds reasonable May 25 03:29:18 weird how that chord has 9 pinx May 25 03:29:30 pins* but I only really need 3 May 25 03:29:38 Tx Rx and GND May 25 03:30:15 DE-9 (often incorrectly called "DB-9") is the standard connector for RS-232 serial ports yes, except for really old ones that use DB-25 May 25 03:30:34 there are a bunch of auxiliary signals that are used in some but not all applications May 25 03:36:52 man if you disconnect with the web browser you can never reconnect May 25 03:37:15 sounds like a bug May 25 05:37:17 trying to get sysvinit/devuan working on debian 10 orig bb May 25 05:37:32 after migration, inittab is used for serial configuration May 25 05:37:37 but i can't get serial access May 25 05:38:30 anyone know the correct tty for orig bb May 25 05:39:43 i have serial from boot until login prompt, at least. May 25 05:51:09 turns out its either ttyS2 or ttyO2 May 25 05:51:15 got it. May 25 06:46:15 hello May 25 06:46:16 Beagle board is not reset. What should I do? May 25 20:26:33 if I want to access usb serial port from my home linux May 25 20:26:45 i need to go to my /dev folder May 25 20:26:49 but which thing is the serial port May 25 20:27:10 I have a usb folder May 25 20:27:24 and a hiddev0 in there May 25 20:27:28 is that it? May 25 20:27:32 no May 25 20:28:03 usb serial ports are /dev/ttyUSB* or /dev/ttyACM* May 25 20:28:04 so this is my linux laptop May 25 20:28:11 on any linux system May 25 20:28:15 ok May 25 22:34:44 how else can I trouble shoot a serial connection May 25 22:35:08 So when I plug in the device into my laptop USB May 25 22:35:17 i see ttyUSB0 come up May 25 22:35:25 does that mean my computer sees a device May 25 22:36:09 would a USB cord plugged in but not attached to anything create a ttyUSB0? May 25 22:36:56 MattB0ne: it's seeing the USB-to-serial converter May 25 22:38:17 I am just using a chord May 25 22:38:19 cord May 25 22:38:27 I am bypassing the BBB and MAX3232 May 25 22:38:36 so I had a USB-RS232 chord May 25 22:38:59 i.e. an USB-to-serial converter May 25 22:39:01 i plugged in jumpers from the Tx and Rx on the device and connected the corresponding pins on the RS322 side May 25 22:39:06 oh oh May 25 22:39:07 ok May 25 22:39:16 so there is a board or something in there May 25 22:39:18 (but one small enough to be built into a plug) May 25 22:39:27 yes May 25 22:39:32 hmmm May 25 22:39:43 so I my fault point is at the device itself May 25 22:39:58 you haven't described what fault you've observed May 25 22:40:00 if I used the shipped config software it works May 25 22:40:09 just no response from the board May 25 22:40:20 loopback test is successful? May 25 22:40:30 all loop backs work May 25 22:40:31 BBB May 25 22:40:37 BBB+Max3232 May 25 22:40:47 and loopback on the USB-Serial May 25 22:40:49 then either the device is incorrectly configured or you're sending wrong commands May 25 22:41:12 or you're using a different baudrate than what's configured in the device May 25 22:41:14 well if I send junk it should send back b'ERR' May 25 22:41:19 I am not getting that May 25 22:42:02 how would it know where a command ends? May 25 22:42:22 are you sending a CR or an LF at the end of the line? May 25 22:43:25 good point May 25 22:43:31 try sending b'FFV\r' or b'FFV\n' using pyserial May 25 22:43:35 first an idiot question May 25 22:43:37 I'll bet one of the two works, probably the first one May 25 22:43:54 on the cord pins May 25 22:44:05 Tx on the device should go to Rx on the plug May 25 22:44:11 or Tx on the plug May 25 22:44:42 manual says TXD on PC side to RXD of EM100 and vice versa May 25 22:44:54 your right May 25 22:44:58 dur May 25 22:45:01 on my part May 25 22:45:12 manuals are pretty useful May 25 22:45:19 -_- May 25 22:45:40 I'll admit the manual doesn't seem to clearly specify what byte is used to terminate commands, unless I've overlooked it May 25 22:46:26 so I'd try CR (b'FFV\r'), LF (b'FFV\n'), or as last resort CRLF (b'FFV\r\n') May 25 22:52:30 hmm no dice May 25 22:52:36 b'' May 25 22:52:59 well, then something is probably still configured wrong :P May 25 22:53:14 lol May 25 22:53:29 the GND on the R232 cord May 25 22:53:32 do I need that May 25 22:54:04 so I have the GNDC going to the GND pin on the USB-to-Serial cord May 25 22:55:13 yes May 25 23:00:23 ok do I need to do anything on the laptop side to configure the USB port for serial May 25 23:00:32 all I did was open from pyserial May 25 23:00:49 pyserial configures it based on the parameters you specify May 25 23:24:32 hmm i am stuck I sent an email to the vendor **** ENDING LOGGING AT Tue May 26 02:59:57 2020