i.MX6Q CSI Parallel Generic Data

[curtis1]

Hello,

We have been unsuccessfully trying to collect generic data supplied by an FPGA over the IPU parallel interface. We have patched the kernel and device tree to enable greyscale/generic data and can receive data into the i.MX6 memory. However, the data is striped with repeated erroneous values.

Consider the following logic analyzer capture,
FPGA_Par_Bus.png

This results in the following pattern in the i.MX6 memory,
iMX6_Bad_Pattern.png

According to the CSI_Timing.pdf from this post we are using so-called JPEG mode. Does this imply that the data is to be formatted as a JPEG?

Can someone further elaborate on the timings specified in that document, and which timing is appropriate for parallel generic data?

Thank you,

Curtis

Edit:

Additional confusion arises from the IMXQRM.pdf, consider figure 37-18
imx6_csi_nongated.png

This agrees with the so-called "non-gated mode" described in CSI_Timing.pdf.

However, figure 37-17
imx6_csi_gated.png

is called "JPEG mode" in CSI_Timing.pdf.

Where does CSI_Timing.pdf come from, and are those timings to be trusted?

[curtis1 · Accepted solution]

We found that the mxc_v4l_open function in the mxc_v4l2_capture module did not properly set the external vsync option. Testing confirms that internal vsync causes the data corruption we see.