On 26 April 2016 at 08:07, florian.feldbauer85 via BeagleBoard <[email protected]> wrote:
>> > I did some further tests. >> > Actually none of the screens from my scope looks like I would expect it... >> > >> > Picture 1 shows the result, if I try to read something on the bus with a >> > 14s >> > timeout (nothing was sended on the bus...) >> > Pic1 >> > Picture 2 shows the same, but this time there were messages send over the >> > bus. After 49 bytes, the beagle bone toggles the DE/!RE gpio to high for >> > unknown reasons (the test program is still reading from the UART interface) >> > Pic2 >> > Picture 3 shows the test, where the BeagleBone is sending >> > Pic3 Your scope picture #3 does appear to show data being sent, however you seem to say that your picture #2 portrays a test in which you received 49 bytes, however I don't see any sign of data being received in that picture. Maybe I am missing something. I am not an expert in these things, but my current understanding is that what the 485 driver provides extra to what the UART driver does is the automatic switch of the driver enable pin. One test I would suggest, a test I have done myself, is to send and receive data with 485 using the UART driver. In this case the DE/RE needs to be set manually. I do it using echo to /sys/class/gpio. Once that is working well you could start test usinging the 485 driver. You should be able to use your existing rs485_test.c program for that. >> @Alex: I recommend, you read my mail ;-) >> I did not look into the kernel source nor am I sure which driver is used in >> my Setup, >> but the problem is not the "rs485-rts-active-high" flag As Micka and Alex said the 4.1 and 4.4 driver do not have 485 support enabled. Per an email by Robert you need to enable the OMAP serial kernel configuration option and rebuild the kernel. -- 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/CAKkGsYKhcGxN78Rsx327GTM5CNOfbkHMN07mwTFg0OqxoCKTZw%40mail.gmail.com. For more options, visit https://groups.google.com/d/optout.
