Author Topic: I2C Acknowledge bit Vl53l1x  (Read 526 times)

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Offline Twos

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I2C Acknowledge bit Vl53l1x
« on: April 01, 2019, 11:34:51 am »
Hi,

I am trying to let my STM32L0 communicate with a VL53l1x. The Device adres is 0x52 and i can see it on my scope but the Ack-bit behaves weird.
The '1' on the I2C line is 3.3V and the '0' is at 0V. My Ack-bit has a value of 1.88V.
I am not sure what to do about this.

Thanks
 

Offline mjs

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Re: I2C Acknowledge bit Vl53l1x
« Reply #1 on: April 01, 2019, 12:03:42 pm »
How have you implemented I2C on the MCU side ? You can get this kind of result if the MCU and device both try to drive the line instead of MCU releasing the pin.
What kind of pull up resistors do you have ?
 
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Offline SiliconWizard

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Re: I2C Acknowledge bit Vl53l1x
« Reply #2 on: April 01, 2019, 03:45:05 pm »
That looks as though either you didn't configure the I/O pins for I2C as open drain, or the pull-up resistors are way too low in value.

 
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Offline Twos

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Re: I2C Acknowledge bit Vl53l1x
« Reply #3 on: April 03, 2019, 10:04:04 am »
There is a pullup resistor in the sensor module and i had pullup configuered in the MCU. Changed the mode to NOPULL and it fixed the problem
Thanks.
 


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