# How to select between two CSI cameras with shared I2C bus? 

**URL:** <https://forums.developer.nvidia.com/t/how-to-select-between-two-csi-cameras-with-shared-i2c-bus/55650>\
**Category:** Jetson TX2\
**Created:** [November 28, 2017, 7:26pm UTC](https://forums.developer.nvidia.com/t/how-to-select-between-two-csi-cameras-with-shared-i2c-bus/55650 "2017-11-28T19:26:03Z")\
**Posts on this page:** 5\
**Page:** 1

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**Author:** ![avew](https://developer.download.nvidia.com/images/forums/profile-default-devtalk-84.png) [@avew](https://forums.developer.nvidia.com/u/avew)\
**Post date:** [November 28, 2017, 7:26pm UTC](https://forums.developer.nvidia.com/t/how-to-select-between-two-csi-cameras-with-shared-i2c-bus/55650/1 "2017-11-28T19:26:03Z")

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The CSI connector on the TX2 has 4 pairs of data lanes (SCI0 D0, SCI0 D1, SCI1 D0, and SCI1 D1) the Sunny camera P5V27C on the TX2 only uses SCI0 D0 and SCI0 D1 data lines. If we want to use a bridge board to hook two Sunny P5V27C camera (and use SCI1 D0 AND SCI1 D1) how do we select between the two cameras? The I2C lines are shared since the CSI connector on the TX2 carrier board only has I2C\_CAM\_CLK and I2C\_CAM\_DAT signals. Thanks for your help in advance.

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**Author:** ![avew](https://developer.download.nvidia.com/images/forums/profile-default-devtalk-84.png) [@avew](https://forums.developer.nvidia.com/u/avew)\
**Post date:** [November 28, 2017, 9:54pm UTC](https://forums.developer.nvidia.com/t/how-to-select-between-two-csi-cameras-with-shared-i2c-bus/55650/2 "2017-11-28T21:54:33Z")

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Is there anyway I can change the address of one of the cameras? I can’t find the datasheet for Sunny P5V27C so I do not know if there exist a pin on the camera to pull up or down to change the address. Any help will be much appreciated.

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**Author:** ![Trumany](https://sea2.discourse-cdn.com/nvidia/user_avatar/forums.developer.nvidia.com/trumany/32/14043_2.png) [@Trumany](https://forums.developer.nvidia.com/u/Trumany)\
**Post date:** [November 29, 2017, 2:57am UTC](https://forums.developer.nvidia.com/t/how-to-select-between-two-csi-cameras-with-shared-i2c-bus/55650/3 "2017-11-29T02:57:59Z")

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Hi avew,

Generally speaking, camera should have such pin for I2C address option, otherwise designer has to use two I2C for two same cameras.

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**Author:** ![snarky](https://sea2.discourse-cdn.com/nvidia/user_avatar/forums.developer.nvidia.com/snarky/32/10446_2.png) [@snarky](https://forums.developer.nvidia.com/u/snarky)\
**Post date:** [November 29, 2017, 3:36am UTC](https://forums.developer.nvidia.com/t/how-to-select-between-two-csi-cameras-with-shared-i2c-bus/55650/4 "2017-11-29T03:36:33Z")

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The other recommendation in the CSI/MIPI integration guide is to use a I2C mux on your camera interface board.  
This in turn needs you to add support for said mux in the driver for the camera(s) so that the driver talks to the right camera.

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**Author:** ![nadeemm](https://sea2.discourse-cdn.com/nvidia/user_avatar/forums.developer.nvidia.com/nadeemm/32/367020_2.png) [@nadeemm](https://forums.developer.nvidia.com/u/nadeemm)\
**Post date:** [October 18, 2021, 6:27pm UTC](https://forums.developer.nvidia.com/t/how-to-select-between-two-csi-cameras-with-shared-i2c-bus/55650/5 "2021-10-18T18:27:33Z")

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