[U-Boot] STM32F746 Discovery - No serial output?

[Francois Dugast]

Thanks for the infos and the patches.

1. Non SPL
After disabling SPL in the U-Boot configuration and enabling USART6 in the
DTS with the patches you provided, there is still no output on this serial
interface after flashing U-Boot v2018.01 (stm32f746-disco_defconfig) with:
$ openocd -f board/stm32f7discovery.cfg -c "program images/u-boot.bin
0x08000000" -c "reset run" -c shutdown
Serial output is coming on USART6 with U-Boot from
https://github.com/EmcraftSystems/u-boot so it is unlikely to be a hardware
issue.

2. SPL
I am not familiar with this mode on the stm32f746 disco. I have tried
copying the u-boot.bin generated with SPL enabled to the "DIS_F746NG" MBED
volume exposed by the card and the LED blinks in red and green for a few
seconds. Still, no output is coming through the /dev/ttyACM* device. Could
you give some hints about the steps to get it running?

Francois

On Tue, Jul 25, 2017 at 3:39 PM, Patrice CHOTARD <patrice.chotard at st.com>
wrote:

> Another update you need to do, is to change the default uart in device
> tree. By default uart1 is used, using the STLink usb port.
>
> To use the UART6 output on arduino UNO connector, applied the attached
> patch.
>
> Patrice
>
> On 07/25/2017 02:20 PM, Patrice CHOTARD wrote:
> > Hi Francois
> >
> > By default, stm32f746-disco is configured in SPL mode, that's what
> > explain you don't get any output in the console
> >
> > To come back in non SPL mode, you can use the attached patch.
> >
> > Patrice
> >
> > On 07/21/2017 10:40 PM, Francois Dugast wrote:
> >> Hi,
> >>
> >> I am trying to run the master on a STM32F746 Discovery board [1] by
> using
> >> stm32f746-disco_defconfig. It was built with
> gcc-arm-none-eabi-5_4-2016q3
> >> [2] and flashed with OpenOCD [3]. A USB-serial adapter is connected to
> >> USART6_RX and USART6_TX (pins D0 and D1 of the Arduino connector) and
> >> configured for 115200 8N1. No output coming out through the serial
> >> interface. It is unlikely to be a hardware issue as output is coming out
> >> normally this way when using the U-Boot repository from Emcraft.
> >>
> >> I do not know what I am doing wrong, can you help me out?
> >>
> >> Cheers,
> >> Francois
> >>
> >> [1] http://www.st.com/en/evaluation-tools/32f746gdiscovery.html
> >> [2] https://launchpad.net/gcc-arm-embedded
> >> [3] http://openocd.org
> >> [4] https://github.com/EmcraftSystems/u-boot
> >> _______________________________________________
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> >> U-Boot at lists.denx.de
> >> https://lists.denx.de/listinfo/u-boot
> >>
> >>
> >>
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