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I am using I2C bus 0 to operate the pis-1690 (CSI camera with I2C on bus0) along with the mlx90640 (I2C camera on the same I2C bus). The cameras are being operated by a Raspberry pi 4 with 8 GB RAM and a Raspbian OS.

Both seem to work well with the default parameters.

When I try to i2cscan the cameras get stuck (no response or one with very large delays). What can be the problem?

winny
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metsik
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    Do the I2C chips support the protocol used by the scanning tool - not all chips do so they can't be detected by protocol used by i2cscan. – Justme Apr 03 '23 at 12:10
  • yes. they also work perfectly when I operate them individually. – metsik Apr 03 '23 at 13:40
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    Do they have same I2C address? Do each have own set of pull-up resistors? – Justme Apr 03 '23 at 13:47
  • *They both work well with the default parameters.* Can you elaborate on this? What have you done with them that works? Have they worked while on the i2c bus together and you're only having problems with i2cscan, or has i2cscan worked but everything breaks once they are on the bus together? – InBedded16 Apr 03 '23 at 14:28

1 Answers1

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[Inspired by Justme's comment.]

Try to lower the I2C data rate. I would try 100kHz. Maybe you are running the I2C bus too fast for one of the devices, and it becomes confused and locks-up the I2C bus.

As an aside, I've done a shared I2C with an Omnivision sensor, and it worked as you'd expect. The other I2C device was an EEPROM.

Nick Alexeev
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