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PSoC 5, 3 & 1 MCU

Anonymous
Not applicable

 Hello,

   

Can anyone tell me how to set I2CHW UM operating voltage to 3.3V or 5V? I set my PSoC1 system power setting to 5V, but the i2cHW still operates at 3.3V. I didn't find anywhere to change the i2c voltage and hope anyone can help out.

   

Thanks!

   

CC

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Anonymous
Not applicable

Do you have pull up resistor to VCC on the 2 I2C pins? what is the voltage on the other side of the resistor?

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Esteemed Contributor

The logic high level for I2C is set by the Vdd supply for

   

the pullup R's. If you are using internal pullups they get

   

powered by whatever the PSOC Vdd is. If you use external

   

pullups and terminate them to 3.3V, noise margin in.

   

this situation significantly reduced. The min "1" level is .7 x Vdd

   

 

   

 

   

 

   

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