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PSoC 5, 3 & 1 MCU

New Contributor

Hey,

I want to be able to use 3.3V logic on my I2C lines of CY8Ckit-059, however I still want to be able to have my KitProg plugged in and get data from it and continue to be able to program my PSOC. Is this possible? How do I do it?

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Esteemed Contributor

Hi,

Note: Dear /odissey1-san, please correct me if I'm wrong

SDA pin and SCL pin are configured as open-drain, so it will not be driven to High (5V).

So "IMHO", as far as you connect only SDA, SCL and GND to CY8CKIT-059 and

you pull-up SDA and SCL lines with 3.3V, the 3.3V logic group will be fine and

PSoC can access I2C without destroying the 3.3V logic group.

moto

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4 Replies
Honored Contributor II

amcl,

Port 12 on KIT-059 is a Special pins (SIO), which can serve as logic level translator for I2C operating at 3.3V , while the rest of PSoC is at 5V. Please read AppNote on SIO use

https://www.cypress.com/documentation/application-notes/an60580-sio-tips-and-tricks-psoc-3-psoc-5lp

Note that I2C communication requires 10k pull-up resistors on both SCL and SDA lines for proper operation.

/odissey1

Esteemed Contributor

Hi,

Note: Dear /odissey1-san, please correct me if I'm wrong

SDA pin and SCL pin are configured as open-drain, so it will not be driven to High (5V).

So "IMHO", as far as you connect only SDA, SCL and GND to CY8CKIT-059 and

you pull-up SDA and SCL lines with 3.3V, the 3.3V logic group will be fine and

PSoC can access I2C without destroying the 3.3V logic group.

moto

View solution in original post

Honored Contributor II

Motoo,

Yes, this should work as long as pins are set to open drain drives low.

/odissey1

Esteemed Contributor

Dear /odissey1-san,

> Yes, this should work as long as pins are set to open drain drives low.

Thank you 😉

Best Regards,

19-Sep-2019

Motoo Tanaka

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