Hi, Will the 8250 driver still allow "manual" control of the RTS line for a given UART from an application like Python or C# (where the application toggles the state of the RTS line, rather than driver, after sending a request message in order to toggle the 485 XCVR), or is the OMAP driver (in place of the 8250 driver) needed for this as well?
I've attempted to associate the RTS line for UART5 with GPIO5_8 (which is connected to the DE toggle on a 485 chip) via the device tree (kernel 4.4.y), followed by calling setRTS(True/False) from Python, but that doesn't appear to be switching the 485 XCVR. However, I can still use sysfs commands to toggle the GPIO5_8 connected to the 485 chip to control the direction of transmission. In order to help differentiate between an incorrect device tree configuration vs. needing to recompile the kernel with the OMAP driver instead of the 8250 driver, I'm wondering if you know whether the 8250 driver will support what we're trying here. Everything I've read (including https://groups.google.com/forum/#!msg/beagleboard/nMtRpdWSJu0/EDSXqGpiBAAJ) seems to suggest that the 8250 doesn't yet handle toggling the RTS/CTS lines on its own based on delays between characters, but I haven't seen anything about manual control. Following is a snippet/fragment from my device tree. ***LATE DISCLOSURE*** >From UART5_8, you can see that this is for the BB-X15, but I believe the same issue pertains to both the BBB and the BB-X15: &uart5 { pinctrl-names = "default"; pinctrl-0 = <&uart5_pins>; status = "okay"; rts-gpio = <&gpio5 8 GPIO_ACTIVE_HIGH>; rs485-rts-active-high; rs485-rts-delay = <0 0>; linux,rs485-enabled-at-boot-time; }; Thanks!!! On Monday, November 13, 2017 at 3:04:51 PM UTC-6, Rnd Mpt wrote: > > We used the rs485 version/branch of the modbus on github. Sorry i meant to > say rts instead of cts. > > I used my github as notes. Follow readmes and see if it helps. Its been a > while since we did this. Let me know if more help is needed > > https://github.com/rwdutoit/beaglebone?files=1 > > On Mon, 13 Nov 2017, 16:33 , <[email protected] <javascript:>> wrote: > >> https://github.com/RobertCNelson/bb-kernel/issues/38 >> >> >> 2017. november 10., péntek 20:33:49 UTC+1 időpontban [email protected] >> a következőt írta: >> >>> Did you ever get this to work >>> >>> I am using the Nelson yakbuild kernel 4.9.45 and disabled the 8250 and >>> enabled omap serial in kernel configuration >>> >>> using same rs485 dtso overkay I can not get RTS to work >>> and nothing transmits. >>> >>> I can not find anything on web to solve this. >>> Do you have a solution procedure? >>> >>> >>> dennis >>> >> [email protected] >> >> -- >> For more options, visit http://beagleboard.org/discuss >> --- >> You received this message because you are subscribed to a topic in the >> Google Groups "BeagleBoard" group. >> To unsubscribe from this topic, visit >> https://groups.google.com/d/topic/beagleboard/JGIm0Ej6jDI/unsubscribe. >> To unsubscribe from this group and all its topics, send an email to >> [email protected] <javascript:>. >> To view this discussion on the web visit >> https://groups.google.com/d/msgid/beagleboard/702f3cd1-c887-4003-9993-aa70998a5b1a%40googlegroups.com >> >> <https://groups.google.com/d/msgid/beagleboard/702f3cd1-c887-4003-9993-aa70998a5b1a%40googlegroups.com?utm_medium=email&utm_source=footer> >> . >> For more options, visit https://groups.google.com/d/optout. >> > -- 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/42f6ff20-b4ae-4974-ac8f-7ea33e32dcc7%40googlegroups.com. For more options, visit https://groups.google.com/d/optout.
