Hi, We are having allot of problems getting RS485 with RTS working on Debian: Linux 4.4 CAn someone help?
On Thursday, March 23, 2017 at 9:13:23 PM UTC+2, [email protected] wrote: > > Hi Alexander, > > The link you provided does not work: > > > http://inspire.logicsupply.com/2014/09/beaglebone-rs-485-communication.html > > > Do you mind sending me the tutorial? I am currently designing my own cape > which will support two RS485 half duplex channels and your tutorial would > be very helpful to get me started. My questions are: > > 1) Am I limited to UART4 or can I use any of the available UARTs on the > Beaglebone Black? > > 2) Just to be 100% sure, I can use any of the GPIO pins for controlling DE > & /RE pins on the RS485 transceiver (I'm using TI's ISO15MDW)? > > Thank you, > > Bolek > > On Wednesday, September 3, 2014 at 10:07:26 AM UTC-7, Alexander Hiam wrote: >> >> I actually just put up a tutorial for doing this in Python: >> http://inspire.logicsupply.com/2014/09/beaglebone-rs-485-communication.html >> >> It uses GPIO1_16, but of course you can use any GPIO pin, including the >> one that's shared with UART4 RTS. >> >> >>> When I tried to use: >>> struct serial_rs485 rs485conf; >>> rs485conf.flags |= SER_RS485_USE_GPIO; >>> rs485conf.gpio_pin = GPIO0_9; >>> >>> I got error from gcc that it does not know those macros: >>> ‘SER_RS485_USE_GPIO’ was not declared in this scope >>> rs485conf.flags |= SER_RS485_USE_GPIO; >>> ‘struct serial_rs485’ has no member named ‘gpio_pin’ >>> rs485conf.gpio_pin = GPIO0_9; >>> ‘GPIO0_9’ was not declared in this scope >>> rs485conf.gpio_pin = GPIO0_9; >>> >>> >> That's because you're compiling with the standard libc headers, which >> don't include the modified serial_rs485 struct that uses the GPIO pin. The >> tutorial I linked above uses Python and just defines the same values >> locally, which you could do in C as well. You could also grab the Kernel >> source and include 'include/uapi/linux/serial.h', which has the patched >> serial_rs485 struct ( >> https://github.com/RobertCNelson/bb-kernel/blob/am33x-v3.8/patches/fixes/0007-omap-RS485-support-by-Michael-Musset.patch#L201 >> ). >> > -- 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/128d1fae-46ac-4e2d-a759-1cb1568f443c%40googlegroups.com. For more options, visit https://groups.google.com/d/optout.
