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iMx6, CSI YUV 8 bit, double data rate

Question asked by Alessandro Innocenti on Aug 13, 2013
Latest reply on Jan 25, 2015 by kamel B
Branched to a new discussion

Hi !

I am interfacing an ADV7403 device to the iMx6(Dual). This device is very similar to the well known ADV7180, it is much more versatile and accepts several video sources (RGB, CVBS, SVIDEO, etc). Due to the fact we have only a 8 bit CSI port (from CSI_12 to CSI_19) we need to use a video format YUV422 at double data rate, DDR. The LUMA data (8 bits) is sent during the rising edge of the clock, the CHROMA data (4+4 bit) are sent during the falling edge.

So we start from adv7180_tvin driver to create the new one. All it'is working well, but 8 bit DDR video packing doesn't.

We enabled the BT.1120 DDR mode, and the  IPUx_CSI0_SENS_CONF register  is set to 0x00008A42. As result we only get the LUMA but not the CHROMA components. I suppose the CHROMA components are transmitted during the falling edge of the clock.

 

To test the driver we use the command mxc_v4l2_tvin -ow XXX -oh YYY, on the LCD screen we have a green level image reporting only LUMA. The same is if we use the gstreamer pipeline:

gst-launch tvsrc ! mfw_isink or gst-launch mfw_v4lsrc ! <caps> ! mfw_isink.

 

Did anybody test the DDR capabilities of iMx6(Dual) ?

 

Thanks.

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