MSP432P401R: GPIO output open drain configuration

Dhafer BEN CHIKHA

Part Number: MSP432P401R

Hello,

I am trying to migrate a software that communicates with a temperature sensor using I2C.
The old software is using a custom driver for I2C communication.

The data line is configured as output open drain. When the data line is released (output = high) the sensor sends data to the microcontroller. the driver does not change the data line configuration to input and reads the data input register. (old part is STM32).

I did not find in the datasheet something that says it's possible to configure a GPIO as output with open drain (except for I2C as data line).

Is it possible to configure a GPIO as output with open drain? and if it is, is there a risk the pin would be damaged if I use it the way mentioned above.

Thank you,

Dhafer.

over 5 years ago

0 Leonardo Estevez over 5 years ago

TI__Genius 12615 points

Hi Dhafer,

According to table 13-1 of the Family User's Guide. I'm only seeing I2C pins with open drain configurability:

https://www.ti.com/lit/ug/slau356i/slau356i.pdf

Hope this helps.

BR,

Leo

0 Dhafer BEN CHIKHA over 5 years ago in reply to Leonardo Estevez

Prodigy 50 points

Hi Leonardo,

Thank you for your reply.
I am wondering if the pins with I2C capability could be configured as output open drain. Most probably it's not possible, but maybe I am missing something.

BR,

Dhafer

0 Leonardo Estevez over 5 years ago in reply to Dhafer BEN CHIKHA

TI__Genius 12615 points

Hi Dhafer,

I think it's possible, but it looks like this is controlled by the EUSCI according to the table referenced above:

PM_UCB0SDA eUSCI_B0 I2C data (open drain and direction controlled by eUSCI)

BR,

Leo

0 Dhafer BEN CHIKHA over 5 years ago in reply to Leonardo Estevez

Prodigy 50 points

Hi Leo,

What if I configure the pin as I2C data line and then use it as output pin with open drain.
What I am afraid of is that the eUSCI changes the pin direction to input.

BR,

Dhafer

0 Leonardo Estevez over 5 years ago in reply to Dhafer BEN CHIKHA

TI__Genius 12615 points

Hi Dhafer,

Typically, there would be a pullup resistor on the I2C lines - are you planning to use it for I2C communication? If so, I would expect it to work.

BR,
Leo

0 Dhafer BEN CHIKHA over 5 years ago in reply to Leonardo Estevez

Prodigy 50 points

Hi Leo,

Right now I can't test if it will work or not, I don't have the sensor, I am working on migrating the software.

What I did is to simply switch between output and input with pull up resistor configurations when needed.

If I tried the other method, I will let you know if it works.

Thank you for your time,

Dhafer

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MSP432P401R: GPIO output open drain configuration