Author Topic: ORG1411-PM04 GPS module - I2C integration without 1.8V  (Read 626 times)

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Offline timmboTopic starter

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ORG1411-PM04 GPS module - I2C integration without 1.8V
« on: January 08, 2020, 04:01:00 pm »
Hi all,

I'm currently designing a circuit including the small ORG1411-PM04 module, which runs on 3.3V (the PM01 runs on 1.8V).

I would like to avoid an external 1.8V LDO, but now ask myself if the I2C SCL and SDA lines will work (IO output level of the ORG1411 is 1.8V). They are pulled up by 4.7k to 3.3V (near my ESP32 MCU).

The ORG1411 datasheet says:"SCL and SDA are pseudo open-drain lines, therefore require external pull-up resistors of 2.2kΩ to 1.8V, or 3.3kΩ to 3.3V.".

Means it should work, right? Even if SCL and SDA are on 1.8V level on ORG1411 side and 3.3V on MCU side? I'm not a big I2C expert.

I attached the schematic (without the 4.7k pull-ups for I2C, they are located near the ESP32 MCU).

Thanks in advance,
Timm
 

Offline mvs

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Re: ORG1411-PM04 GPS module - I2C integration without 1.8V
« Reply #1 on: January 09, 2020, 12:41:45 pm »
The ORG1411 datasheet says:"SCL and SDA are pseudo open-drain lines, therefore require external pull-up resistors of 2.2kΩ to 1.8V, or 3.3kΩ to 3.3V.".
Means it should work, right?
Yes

Quote
Even if SCL and SDA are on 1.8V level on ORG1411 side and 3.3V on MCU side? I'm not a big I2C expert.
You will get I2C with 3.3V levels on both sides. But it is fine, since ORG1411 inputs are 3.3V tolerant and I2C output (SDA) is open drain.
 

Offline timmboTopic starter

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Re: ORG1411-PM04 GPS module - I2C integration without 1.8V
« Reply #2 on: January 09, 2020, 04:31:42 pm »
Cool, thank you very much for the help! Greets, Timm
 


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