In order to provide longer delays without wasting too much inline code space, the delay_50usec() and delay_msec() functions are used. These 2 functions represent a variable number of delay periods based on 50 microseconds and 1 millisecond respectively.

Notice that we have now introduced parameter passing as arguments to functions. Both of these functions contain the unsigned char delay declaration within the parentheses of the function declaration. This means that when we call them from another function we need to provide a number as an argument which in both cases represent the number of time delays.

Both function internally declare a variable x as an unsigned char. Remember that an unsigned char is an 8 bit number ranging from 0 to 255 (or 0x00 to 0xff in hex or 0b00000000 to 0b11111111 in binary). Since the variable is declared within the function it's scope is limited to the function only and cannot be seen by other functions.

The for loop is now executed a number of times as specified in the delay parameter passed to them. In the for loop, x is first initialized to 0 and the for loop is executed as long as x is less than the value in delay. The last statement in the for loop increments to variable x at the end of each loop.

The function delay_50usec() uses a variety of #define's at the top of the file to cause each execution of it's for loop to delay 50 microseconds.

The function delay_msec() calls the delay_50usec() with an argument of 22 to provide a 1 millisecond delay each time it's for loop is executed.