A microprocessor system includes three parts: $1)q,$

$21)q,$

$2.$ A touch screen has functions of two kinds of device: $1^{**}-$

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$3.$ A microprocessor is controlled by a program, and the program should saved in $$

$($ROM$,$ RAM$)$ type memory becau: $$

$q,$

$4.$ What is the difference between ROM and RAM? $($list two difference facts$)$

$5.$ A signal pin of a microcontroller has several functions, such as input, output, analog input etc. How to specify the function of a signal pin?

$6.$ Answer the following questions according to the following circuits:

$$

a$.$ What is the function of resistors R$79?$