Hi, I'm running on a BB-X15 with kernel 4.4.110-ti-r142 and Debian, 8.10 (2018-01-01).
I have not yet correctly run hardware flow control on Beagleboard-X15/BBB, but I BELIEVE I saw evidence that the non-default, OMAP serial driver (as opposed to the default 8250 serial driver) was auto-toggling the RTS line when the RTS line was using a GPIO line instead of a "dedicated RTS line" for the respective UART. Caution: it could be that the driver was treating the GPIO line differently than the dedicated RTS line, so I need to go back and flush all of this out (unless someone on here already knows the answer)... I also need to show you the difference in how my device tree fragment for this UART was specified. Furthermore, since we're doing RS485/MODBUS for our work project, our strategy (at the moment) is to manually toggle the dedicated RTS line which is connected to the "DE switch" on a 2-wire RS485 chip. Toggling the DE switch switches whether the half-duplex RS485 chip is transmitting (e.g. UART port's Txd line is connected) or receiving (e.g. UART port's Rxd line is connected). One interesting thing to note, is that so long as we use a "dedicated RTS line from the UART, we can manually toggle that RTS line (in Python, for instance) regardless of whether we're using the OMAP driver or the 8250 driver. My BB-X15 is currently setup for UART 9. The pinmux has been configured to expose UART9's Rxd, Txd, RTS, and CTS. I just need a good, easy way of testing hardware flow control maybe in some kind of real time data exchange. So maybe something like a Python program running on both my PC and my BB-X15 which boomerangs back what the other party sends??? I will TRY to test this this week in my spare time, but there's some stuff at work and outside of work this week which could easily necessitate pushing this back.. So bare with me, and follow-up if I drop the ball. Thanks! Jeff On Saturday, February 3, 2018 at 8:30:27 PM UTC-6, [email protected] wrote: > > I've been using a beaglebone black (in debian) to communicate with my > Matsuura MC800 VF (1993). It's got an old yasnac I-80 controller on it, and > I have to drip feed most stuff because I've only got about 30k of program > memory. For the record I was unable to get this to work with USB to serial > adapters, in both Windows and Linux. As soon as I went directly to the UART > pins it was easy. > > I recommend using stty to set the serial port, and the just copy the file > you want to the serial port. For example, I run at 4800 baud, 7 data bits > even parity 1 stop bit with software "flow control". Here's how I set the > port settings for the beaglebone black: > > stty -F /dev/ttyS1 4800 parenb cs7 -icrnl ixon nl1 cr1 > > > then do something like this to copy the file to the serial port and have > the beaglebone spit it out. In my case I'm using serial (uart) 1: > > cp /pathtofile/mycncfile.nc /dev/ttyS1 > > > You can do it in Python, but I'd get it working at the most basic level > first. With Python there could be additional software buffers between you > and the cnc machine that could cause issues. > > > I use a max232 between the beaglebone and the machine for level shifting. > I'm currently using an old one a buddy soldered up and had laying around, > but I'm going to put in a more professional max232 in the next couple days. > The one I got was on Amazon link here: > > > https://www.amazon.com/gp/product/B00HKIMBZW/ref=oh_aui_search_detailpage?ie=UTF8&psc=1 > > > It looks, good, but I haven't tested it yet. > > > > Now, I've got a question for you guys. Has anyone been able to get > hardware flow control working on the beaglebone black in debian? > > > -Marc > > > > On Wednesday, November 15, 2017 at 1:49:26 AM UTC-8, Jeff Andich wrote: >> >> Yeah we also stumbled last-week on Tx and Rx being swapped/ ‘crossed’ for >> UART1 (?only?) on the BB-X15 AND TI 572x evm REVA3 schematics. The other >> UARTS appear fine. Details to follow. > > -- For more options, visit http://beagleboard.org/discuss --- You received this message because you are subscribed to the Google Groups "BeagleBoard" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To view this discussion on the web visit https://groups.google.com/d/msgid/beagleboard/13bd8cf2-5482-4d4f-bbda-fd624b4b57ff%40googlegroups.com. For more options, visit https://groups.google.com/d/optout.
