Can the STM32N6 be connected to a 12MP image sensor

zeal_liu · ‎2025-02-25

Can the STM32N6 be connected to a 12MP image sensor for use solely in taking photos?

In Section 3.25 of the datasheet, it is mentioned:

"The DCMIPP path offers the following summarized maximum features:
• Target sensors: 5 MPixel at 30 fps max"

AND

"Some over-target use cases are possible, but with specific constraints:
• sensors with resolution above 5 Mpixels
• sensors with pixel rate above 150 Mpixel/s
• double sensors in parallel"

I know that STM32N6 can only support video of 5MP@ 30fps. However, if I only use it for taking still images, can the input pixel resolution be greater than 5 MP?Like 12MP (IMX681)

In Section 3.31 of the datasheet, it is mentioned:

" Still-image encode:
– codecs: JPEG (baseline interleaved)
– performance: 300 Mpixel/s for JPEG"

From my understanding, from the VENC perspective, it should be able to support higher pixel resolutions for still images as well. However, there is no explicit mention of this in the datasheet. Could everyone please help clarify my doubt?

VABRI · ‎2025-03-12

Dear @zeal_liu,

The DCMIPP of the STM32N6 has an ISP inside. The ISP is designed to support up to 5Mpix resolution.

If the sensor you want to connect is a RAW Bayer sensor then a miximum of 5 Mpix resolution can be supported.

Connecting a 12Mpix Raw sensor is fine but only 3 Mpix of this sensor can be supported by the ISP of the DCMIPP thanks to the decimation block that will reduce the 12Mpix to 3 Mpix by applying a division factor of 4.

In other hand, I you want to connect a 12Mpix RGB/YUV sensor, the sensor stream can be retrieve using the pipe0 of the DCMIPP that will only dump the output of the sensor. From that point of view 12Mpix sensor is supported by the STM32N6 DCMIPP only if this sensor does not need ISP processing neither post processing like downsize.

Keep in mind that connecting 12Mpix RGB sensor will require 36MB of hyperRam to store the image and according to the XSPI bandwith, the framerate will need to be adjusted.

Hope it clarifies.

BR

Vincent

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