I2C Bus communication error - missing ACK

Discussion related to "under the hood" OpenMV topics.
alexflok
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Joined: Tue May 05, 2020 11:29 pm

I2C Bus communication error - missing ACK

Postby alexflok » Tue May 05, 2020 11:33 pm

I have an error pop up when I am trying to run python code (thermal sensor). Error:"I2C Bus communication error - missing ACK"
I am using AMG8833 and OpenMV H7 camera.
I am connecting GND to GND; 3.3V to VIN; SCL to P4 and SDA to P5. Do I need connect something else?

Thank you.
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iabdalkader
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Joined: Sun May 24, 2015 3:53 pm

Re: I2C Bus communication error - missing ACK

Postby iabdalkader » Wed May 06, 2020 11:29 am

This issue has been fixed in the latest firmware (3.6.2)
alexflok
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Joined: Tue May 05, 2020 11:29 pm

Re: I2C Bus communication error - missing ACK

Postby alexflok » Wed May 06, 2020 9:26 pm

Unfortunately it's still showing the same error.
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iabdalkader
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Re: I2C Bus communication error - missing ACK

Postby iabdalkader » Wed May 06, 2020 9:34 pm

Could be a wiring issue, please double check the connections (try different/shorter wires)...Do you have the H7 or H7-plus ? And are you using the Sparkfun breakout board ? If not you may need to add pull-ups to the SCl/SDA lines. Also please post the code.
alexflok
Posts: 5
Joined: Tue May 05, 2020 11:29 pm

Re: I2C Bus communication error - missing ACK

Postby alexflok » Wed May 06, 2020 10:18 pm

It was wire. Now I don't have this error.
Thanks for your help!
alexflok
Posts: 5
Joined: Tue May 05, 2020 11:29 pm

Re: I2C Bus communication error - missing ACK

Postby alexflok » Wed May 06, 2020 10:48 pm

I am getting another issue now. My thermal scanner showing just 0 and blue screen.
I double check wire and I think it's connect right(gnd->gnd;3.3v->vin;p4->scl;p5-sda)
I also try to run this code but it's not showing anything.

Code: Select all

i2c = I2C(2, I2C.MASTER)
for a in i2c.scan():
    print("0x%x"%(a<<1))
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iabdalkader
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Re: I2C Bus communication error - missing ACK

Postby iabdalkader » Fri May 08, 2020 7:44 am

I still don't know what camera you're using but anyway, we're going to update and fix the I2C code used for FIR sensors very soon, so this issue should be fixed soon.
alexflok
Posts: 5
Joined: Tue May 05, 2020 11:29 pm

Re: I2C Bus communication error - missing ACK

Postby alexflok » Fri May 08, 2020 8:17 am

I am using H7 camera with adafruit AMG8833
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iabdalkader
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Joined: Sun May 24, 2015 3:53 pm

Re: I2C Bus communication error - missing ACK

Postby iabdalkader » Mon May 11, 2020 9:02 am

Hi, I've updated and fixed all the I2C code, and tested AMG8833, MLX90621 and MLX90640 on OMV3, OMV4 and OMV4P... and they're all working fine. The attached firmware image should fix any issues with AMG8833 please try it and let me know.
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firmware.zip
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