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GPIO Open-Drain I2C Bit Bang MK02FN128VFM

Question asked by Philipp Laemmler on Jul 9, 2015
Latest reply on Jul 10, 2015 by Earl Orlando Ramirez Sanchez

Hello everybody


I want to intergrate a I2C BitBang on two of the GPIO Pins. The Kinetis processor should work as master.

Therefore I have to configure those pins as open-drain output connected with external pull up resistors.

Once the Master has send out the I2C Adress, it has to check the I2C_SDA like for the acknowledge of the slave.

The slaves gives the acknowledge by pulling the signal line low, but unfortunately when I read the GPIO with GPIO_DRV_ReadPinInput(), I get always a 0x01.


I'm a little bit confused about one sentence in the user manual of MK02FN128VFM.


The GPIO input data register

displays the logic value on each pin when the pin is configured for any digital function,

provided the corresponding Port Control and Interrupt module for that pin is enabled.


Can anybody help me to do the right configuration?


Thanks in advance.


Regards Philipp