As we mentioned before, the pin names of the Raspberry Pi and the iMX7D are different. You can take a look at the pinout diagrams in the Appendix, and I suggest that you print them out to have them at hand.
Have the pinout diagram of your developer kit at hand.
When we flipped the Rainbow HAT, we could see that the red LED was wired to BCM6, which is pin 31 of the board. While the pin position is the same, that pin on the iMX7D is called GPIO2_IO02.
However, if we look at the source code of the Rainbow HAT driver, which is in Java, we see that it is accessed using a function.
public static Gpio openLedRed() throws IOException {
return openLed(BOARD.getLedR());
}
This is a concept that is used frequently on examples when you want them to work on both devices. At the very minimum you should use a constant for the pin, so if someone has to...