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Visitor II
November 17, 2023
Question

[stm32f439] I have a question regarding DCMI AV camera capture with TW9912

  • November 17, 2023
  • 1 reply
  • 1073 views

The configuration and operation settings are as follows
H/W : STM32F429<====TW9912<====AV CAMERA
TW9912 is renesas video decoder

The pixel clock was confirmed to be 54mhz. Verified vsync/hsync operation.
There was no problem with the tw9912 settings.

Question 1) When I do the Hsync Line Count, line 525 is correct and
the 60hz image detect status has been displayed since the status register was read. I checked and at this time, I know it is 1440 bytes from the Line Start Code (SAV), but it becomes 1588.
I don't know why?

Question 2) Since Vsync is applied twice, I think I should use ODD field once and EVEN field once.
I try to capture it, but it doesn't reach 240 lines. The number of lines is different each time.
Please help me!!!
Thank you for reading

This topic has been closed for replies.

1 reply

KDJEM.1
ST Technical Moderator
November 17, 2023

Hello @nanoeye2023  and welcome to the community :),

Are you using Embedded data synchronization mode: mode1?

If yes, note that the frame structure using this mode is shown below:

KDJEM1_0-1700212860582.png

but it doesn't reach 240 lines. The number of lines is different each time. 

How many lines you've reached? Are you using Image resizing feature?

Thank you

Kaouthar

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