ESP32 OV2640 camera with internal generator

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Joined: Thu May 03, 2018 10:43 am

ESP32 OV2640 camera with internal generator

Postby BORISBRITWA » Mon Feb 11, 2019 12:02 pm

i trying to use project with wemos lolin32 ... 2_16x9.jpg

The project has the following settings xclk_freq_hz = 20000000 Camera clock frequency in .ino files.
But further in the library(ov264_drive.c) this frequency decreases for SVGA clkrc=0x83 means to divide by four with
internal frequency divider that is inside the camera(PLL).It turns out that the camera clocks 5 MHz for SVGA.
I use the same type of camera with only one difference.The camera is clocked by its own 12 MHz generator
0v2640.jpg (61.97 KiB) Viewed 720 times
Wires between the board and the camera are shorter than 2 centimeters.
I tried to change the clocking settings of the camera 12/2(clkrc=0x81) or 12/3(clkrc=0x82)but it does not give good results.

it looks like 12s is also set to 20Mhz in camera.c
// Configure clock divider
I2S0.clkm_conf.clkm_div_a = 1;
I2S0.clkm_conf.clkm_div_b = 0;
I2S0.clkm_conf.clkm_div_num = 2;

I have done some experiments with the original board TTGO T-Journal.
1.xclk_freq_hz = 10000000
2.(clkrc=0x81)for SVGA
and it works almost good.

Should my camera with an internal generator work with some changes in the project?
If not, why not?
I do not want to unsolder the generator on the board :roll: .

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