RS485 DE signal control

[dsalnikov]

Hi, I have olinuxino-a10lime board with 4.1.3 kernel and libmodbus 3.0.5
I use:
modbus_rtu_set_serial_mode(ctx, MODBUS_RTU_RS485);
but nothing happens. DE still on 0 level.
How can I control DE signal ?

[itiserik]

Neither olilinuxino nor the allwinner a10 has native 485 mode (i.e. the at91sam9g45 has one look, at its datasheet)

Perhaps you can apply the patches in #156.

[karlp]

some of modern kernels have started providing a way of providing a gpio to handle this from the kernel, but yeah, this is a very very unused part of the kernel, and the libmodbus hooks rely on the kernel doing the right thing.

[dsalnikov]

Hi, again!
I recently updated my libmodbus to 3.1.2 version. On olinuxino-a10lime I used modbus_rtu_set_rts function and DE signal changes normally.

ps I have a delay issue, I'll test it on weekend.

[stephane]

Great, one more reason to release libmodbus 3.2 and to inform all Linux
distros.

2016-02-11 9:23 GMT+01:00 Dmitrey Salnikov notifications@github.com:

Hi, again!
I recently updated my libmodbus to 3.1.2 version. On olinuxino-a10lime I
used modbus_rtu_set_rts function and DE signal changes normally.

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Reply to this email directly or view it on GitHub
#311 (comment).

[dsalnikov]

I tested library from main brunch and all is okay.