register value ov5640_read_reg(0x5587,&value) is zero

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register value ov5640_read_reg(0x5587,&value) is zero

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gbiradar
Contributor IV

Hi Guys,

I have first set the value in ioctl_s_ctrl --> V4L2_CID_BRIGHTNESS --> ov5640_write_reg(0x5587,0x40) --> 100millisecond delay -->  ov5640_read_reg(0x5587,&value) --> value = 64.

then i'm trying to read bright value from contrast register in ioctl_g_ctrl --> V4L2_CID_BRIGHTNESS --> ov5640_read_reg(0x5587,&value) --> value = 0, but the return value is zero and argument value is zero.

can any one has idea why the values are turning zero.

NOTE: delay of 100ms is just to read whether register value is resetting or not after writing.

regards

Ganesh Biradar

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jimmychan
NXP TechSupport
NXP TechSupport

The brightness control is not just writing a value to the 0x5587. You need to write 3 different registers to adjust the brightness. Please contact OmniVision or their supplier (the camera you buying from) to request the OV5640 Application Notes. In the application note, you can find the function to control the brightness.

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gbiradar
Contributor IV

Hi jimmychan

jimmychan wrote:

The brightness control is not just writing a value to the 0x5587. You need to write 3 different registers to adjust the brightness. Please contact OmniVision or their supplier (the camera you buying from) to request the OV5640 Application Notes. In the application note, you can find the function to control the brightness.

yes what you said is correct it has three more register i have the document to set brightness value. but while i'm reading this particular register it returning zero value.

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jimmychan
NXP TechSupport
NXP TechSupport

I am not sure if the value may also affected by other functions such as AEC. You may try to turn off other 'auto' features to test. I think you are better to contact OV for official technical support. Because most of their camera information/document are confidential.

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