Explain how to make interrupt in every 100ms by Timer/ Counter in Atmega128a. Explain how to set Port E4~E7 as Pull-up & Input mode for making the button input of the calculator.

(Refresh time of LCD displayer in the caluclator experimental board is about 5ms~10ms. You want to make Timer/Counter Interrupt every 100ms when the setting is given. If you use 16MHz Clock Source, then interrupt should be occurred in every 1,600,000 Clock for 100ms. However, the maximum value of Timer/ Counter in Atmega18a cannot represent 1,600,000. Explain how to solve this problem).