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Camera board • Re: Higher exposure time for OV9282 driver using continuous clock

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Mods: This really should be a continuation of my previous topic on this.
If you want a thread reopened, then use the report button (exclamation mark in a triangle) and ask the mods to do so.

I've just tested both options on a Pi4:

dtoverlay=ov9281

Code:

pi@raspberrypi:~ $ rpicam-hello --list-camerasAvailable cameras-----------------0 : ov9281 [1280x800 10-bit MONO] (/base/soc/i2c0mux/i2c@1/ov9281@60)    Modes: 'R8' : 640x400 [309.79 fps - (0, 0)/1280x800 crop]                  1280x720 [171.79 fps - (0, 0)/1280x720 crop]                  1280x800 [143.66 fps - (0, 0)/1280x800 crop]           'R10_CSI2P' : 640x400 [247.83 fps - (0, 0)/1280x800 crop]                         1280x720 [137.42 fps - (0, 0)/1280x720 crop]                         1280x800 [114.93 fps - (0, 0)/1280x800 crop]
dtoverlay=ov9281,clk-continuous

Code:

pi@raspberrypi:~ $ rpicam-hello --list-camerasAvailable cameras-----------------0 : ov9281 [1280x800 10-bit MONO] (/base/soc/i2c0mux/i2c@1/ov9281@60)    Modes: 'R8' : 640x400 [325.52 fps - (0, 0)/1280x800 crop]                  1280x720 [180.51 fps - (0, 0)/1280x720 crop]                  1280x800 [150.97 fps - (0, 0)/1280x800 crop]           'R10_CSI2P' : 640x400 [260.42 fps - (0, 0)/1280x800 crop]                         1280x720 [144.40 fps - (0, 0)/1280x720 crop]                         1280x800 [120.76 fps - (0, 0)/1280x800 crop]
Streaming at 319fps or above does appear to give black images in R8 mode, or 255fps or above in R10 mode, although the sensor is still streaming. That probably means that the min vertical blanking is incorrect.
The datasheet lists a max of 210fps at 640x400, so I'm not fussed about it.

The framerate calcs are correct in R10, but appear to be about 4.3% low in R8 mode. That probably means the pixel rate is wrong, but the datasheets I have give no extra information on how the clocking structure is changed for 8bit mode. The old ov9281 driver used the same values and register settings there, so that was probably also out.

DT docs would be at https://www.raspberrypi.com/documentati ... html#part2
Device tree bindings (what is and isn't valid for a device) would be https://github.com/torvalds/linux/blob/ ... v9282.yaml for OV9282, to be read alongside https://github.com/torvalds/linux/blob/ ... faces.yaml

Statistics: Posted by 6by9 — Mon Dec 22, 2025 4:56 pm



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