Download example$\_2.$ino and example$\_3.$ino from webcampus, these examples demonstrate two

different ways to implement GPIO at the register level.

$$ A er compiling, the Arduino IDE lists the memory consumption for both program

data, and variable data in the terminal window at the bottom of the IDE, comparing the

memory consumption of all three examples.

$$ Modify example$\_2.$ino and example$\_3.$ino to maximize the frequency output on PB$7.$

What are the frequencies achieved?. Is there any difference in the maximum frequency

output between examples $1$ through $3?$ What explains the frequency differences?