OPI Zero, UART2 RTS CTS don't work

[maxfed3]

Hi All!

OS  - ARMBIAN 5.38 stable Debian GNU/Linux 9 (stretch) 4.14.18-sunxi

OPI Zero.

 

armbianEnv.txt :

overlay_prefix=sun8i-h3

overlays=uart2

param_uart2_rtscts=1

 

RTS CTS don't work

 

I check the work of the logical analyzer. The line RTS does not change the voltage during the request for data transmission. This is necessary for me to connect the MAX485 chip to UART2 OPI Zero.

Edited May 29, 2018 by maxfed3

[martinayotte]

Right, looking at source of sun7i-a20-uart2.dts overlay, it seems that rts/cts pins are not managed as it should ...

 

[maxfed3]

What solutions are available?

[martinayotte]

No easy one ...

The following piece of DT need to be added to "pio" of the main DT.

Maybe that could be done with an overlay, but still requires some work ...

                        uart2_rts_cts_pins: uart2_rts_cts {
                                pins = "PA2", "PA3";
                                function = "uart2";
                        };

 

[zador.blood.stained]

5 hours ago, martinayotte said:

Right, looking at source of sun7i-a20-uart2.dts overlay, it seems that rts/cts pins are not managed as it should ...

Are we talking about A20 or H3?

[martinayotte]

@zador.blood.stained

Since OP mentionned OPiZero in the title, I presume that current patch "sunxi-h3-h5-uart3_rts_cts_pins.patch" should be extended for uart2 also ...

But the "sun8i-h3-fixup.scr" would also need to be extended too !

 

[maxfed3]

When will it be possible to enjoy the normal operation of RTS and CTS UART2 ?

Instructions for applying patches will be required.

[martinayotte]

I'm not sure "when". We will try to add that soon ...

[maxfed3]

how are things with RTS and CTS UART2 ???

[martinayotte]

Didn't get change to work on it yet ...

"Time is the missing ingredient" !

 

[maxfed3]

If I put the latest updates, then the problem with UART2 will be solved?

[martinayotte]

I've done this fix to patches : https://github.com/armbian/build/commit/e0382d1ad2e5ac2c8d4dda814949f989812be18c#diff-33d9868ed154988dc938219a3df6f54d

But I've not got chance to test it.

BTW, this is for the "sunxi-next" builds ...

(I will do the same for "sunxi-dev" today)

[maxfed3]

Since I have not previously done this kind of work, you will need an instruction How to install these patches on the specified system

but, I will be able to check the operation of RTS and CTS signals

[martinayotte]

Since the Armbian doesn't have a recent "next" build in https://dl.armbian.com/orangepizero/ , you will need to build your own image using procedures explained here :

 

https://docs.armbian.com/Developer-Guide_Build-Preparation/