Custom callback code: Now, create a new global variable, initializing it to zero, for storing the

time in milliseconds. Create a second global variable $($also initialized to zero$)$ to store the time

in seconds.

Implement custom code in timer$\_$callback$()$ that increments the new ms counter variable

every time the function is called.

Implement logic that ensures that if the current time in milliseconds is equal to or greater

than one second, it:

Decrements its own value by the ms equivalent of one second.

Increments the seconds variable by the equivalent of one second.

Toggles the on$-$board LED digital output

Note: This code should work if the time in ms is any value over than $1$ second.

Note $2$: This code should be written so as it doesn't reset, clear, truncate, or lose time

information.

In the while loop in main$(),$ add code that

computes the current time as a float in seconds $($with milliseconds behind the decimal

point$)$

fills and prints a string with the current time in seconds, starting with $"t="$ and ending with

$"$s$"$ using

Example:

$t=45\mathrm{.}34s$

Note: It is bad practice to put printf$()$ or sprintf$()$ functions in a callback because it takes so much

time to process.