The FRDM-K22F is an ultra-low-cost development platform for Kinetis K Series K2x (K22F) MCUs built on ARM® Cortex™-M4 processor. Features include easy access to MCU I/O, battery-ready, low-power operation, a …

Conflict between I2C pins on Arduino-compatible header and OpenSDA UART interface

09 Aug 2016

This would be good to have documented somewhere.

On FRDM-K22F, the same signals from the MCU used for D14 and D15 are also connected to the Open SDA (debug circuit) uart connection (UART1_TX, UART1_RX) for virtual com port.

So, if you are using a shield that requires I2C operation on D14, D15, then don't expect the usb virtual com port interface to continue to work and vice/versa. You can possibly jump back and forth between functions if you re-initialize the desired function each time.