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Question regarding VADC feeding to CSI module

Question asked by David Trinh on Dec 8, 2015
Latest reply on Dec 9, 2015 by David Trinh

Hi guys,

I have 2 questions regarding the NTSC video input (Vadc) of the i.MX6soloX SoC.

I currently have a problem with reading the NTSC camera through Vadc using CSI port. However, CSI captured data is only dummy values. I reviewed the mxc_vadc.c driver to find out how data is handed over to CSI from Vadc module.

Question #1: Everything on the vadc driver as well as CSI driver in fsl_csi.c seem to be good. Only one thing I got confused is in the IOMUXC_GPR_GPR5 register. The bit field #28-27 in this register in the CSI2_MUX_CTRL for the CSI2 port. It says 2 things that I don't know:

CSI2 input mux control

- 00 CSI2 takes input from external pins (configured via IOMUXC)

- 01 CSI2 takes input from the composite video decoder

- 10 CSI2 takes input from the VADC-to-CSI capture circuit

- 11 CSI2 inputs are tied to GND.

My question is: What is the different between "CSI2 takes input from the composite video decoder" and "CSI2 takes input from the VADC-to-CSI capture circuit" ?!?

What is the composite video decoder?! how is it different from the embedded decoder in the VADC-to-CSI capture circuit?! I tried to set the input using VADC-to-CSI and result is "No SOF detected". But If I use the "input from composite video decoder", then I always have SOF no matter the NTSC camera is connected or not.


Question #2: When I try to capture 1 frame from the CSI data with YUV444, fram size is 720x480 pixels, I got only 720*480 bytes (not words) of the data, remaining is 0xFF. This means the DMA controller is passing only 720x480bytes to the FB1/2. Meanwhile the CSIFBUF_PARA and CSIDMASA_FB1/2 parameters are correctly set for 720x480 words size.

My question is: do I need to do any further setting in the CSI driver to have a full-frame data captured?!


Also, in the reference manual for the chip, sometime say "video decoder", sometime says "TV decoder". Is it the same embedded video decoder on the chip? or something else?!! Am I missing something here!? So confused.

Can anybody give me some advice/tips for this?!

Also, is there anybody got the NTSC video input works with the i.mx6solox?! could you share the driver version, please?!

(I am using yoto with kernel 3.10.53xx version.)

Thank you!