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/50b1a526-2ca1-4f20-92b8-0b497da1c975%40googlegroups.com. For more options, visit https://groups.google.com/d/optout.
