PrabuKumar's WinCE Blog

June 14, 2008

PXA320 QCI Issue

I have been working on the camera driver for PXA320 processor.We have ported WINCE 6.0 on this board.We were able to capture 640×480 images from the sensor using PXA320 QCI interface.But in the captured images we are getting first line as black.This is due to invalid data for the first line. We struggled to find out exactly why this is happening and due to what. There are three options for this problem

a. Problem might be with the sensor which will be giving one line less data (i.e. giving only 479 line instead of 480).We have tested this by probing the MSB(D7) data line for the first line.From this we confirmed that we are getting the valid 480 lines from the sensor.

b. Problem might be with the DMA data buffer.Since PXA320 is having dedicated DMA channels,there is only less chance to miss the data by the DMA channel.

c. Problem might be with the QCI controller of the PXA320.For this we contacted Marvell for the support and finally got the message that “PXA320’s QCI interface which cannot correctly store the first line of sensor data”.

To workaround for this issue you can configure the sensor to output one extra line.

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