DCMI frame event / line event vs capture rate

[Bertrand1]

Hello,

I have question about DCMI :

I set DCMI with a capture rate with DCMI_CR_ALTERNATE_2_FRAME

I toggl pin in callback to see in my digital scope

First line : line event ( green line)

4th line : frame event ( green arrow)

I assume that the DMA copy the image capture in the ram buffer with le line event synchronisation.

1st remark : Why the frame event callback rise at the begining of the capture? I was expected it was at the end

2d remark : Even if I set alternate capture, why I received line event ( surround in red). I hope there is no copy in ram during this time? Am I right?

Many thanks for you help to understand.

Bertrand

[Hagen1]

Hi Bertrand,

 

Thanks for the detailed problem description! I've come across exactly the same problem, and I wonder if you ever found a solution to it? I guess I could either set a timer or count the line events after the frame start, but surely there must be a cleaner solution?

 

Best,
Hagen