i.MX ProcessorsのトピックRe: Nitrogen6X Lilliput

Nitrogen6X Lilliput

BrianEdmond — Thu, 03 Apr 2014 00:10:25 GMT

I have a 7" Lilliput 669B LCD with a Boundary devices Nitrogen6X and the Yocto build. I would like to run the HDMI at 800x480 and force this resolution. I tried to set it but it just reverts back to the 720x480 resolution. Has anyone gotten a non-standard HDMI mode to work with this image?

Also I would like to use the touchscreen on my board which is a capacitive touch Atmel maXTouch. It is listed in the USB devices but tslib gets 0 for all the press corrdinates. Has anyone used this touchscreen with the Nitrogen6x yocto build.

Thanks,

Brian

Re: Nitrogen6X Lilliput

EricNelson — Thu, 03 Apr 2014 00:57:14 GMT

Hi Brian,

This is a long, sordid story, but I'll try to summarize:

The default kernel from Freescale only supports "CEA" modes (common resolutions for consumer electronics) because there are clocking issues within the kernel. In essence, there are only a handful of divisors of the video clock to get proper audio output over HDMI.
We naively bypassed this check, then started hearing about troubles with audio,
Then we imposed a requirement for a kernel parameter "mxc_hdmi.only_cea=0" and made the default =1
You can over-ride this by setting "allow_noncea" to 1 in U-Boot, but you will get screwed up audio playback over HDMI.
```
U-Boot > setenv allow_noncea 1
U-Boot > saveenv && boot
```

You can read more about it here (with references to the sources):

http://boundarydevices.com/hdmi/

The boot script fragment is here:

u-boot-imx6/board/boundary/nitrogen6x/6x_bootscript.txt at production · boundarydevices/u-boot-imx6 · GitHub

Re: Nitrogen6X Lilliput

EricNelson — Thu, 03 Apr 2014 00:59:21 GMT

Hi Brian,

I forgot to answer your question about the Atmel MaXtouch USB driver...

We haven't seen one of these, so there's currently no support in the kernel tree.

We do have support for an I2C version of a MaXtouch controller, though it's not enabled in our standard configurations.