A microprocessor scans the status of an output I/O device every 20 ms. This is accomplished by means of a timer alerting the processor every 20 ms. The interface of the device includes two ports: one for status and one for data output. How long does it take to scan and service the device, given a clocking rate of 8 MHz? Assume for simplicity that all pertinent instruction cycles take 12 clock cycles

Respuesta :

Answer:

0.0000045 s

Explanation:

f = Frequency = 8 MHz

Clock cycle is given by

[tex]\dfrac{1}{f}=\dfrac{1}{8\times 10^6}=1.25\times 10^{-7}\ s[/tex]

Time taken for 12 clock cycles

[tex]12\times 1.25\times 10^{-7}=0.0000015\ s[/tex]

Time taken per instruction is 0.0000015 s

In reading and displaying information it requires 3 processes

1 for reading, 1 for searching and 1 for displaying.

[tex]3\times 0.0000015=0.0000045\ s[/tex]

Time taken is 0.0000045 s

We have that for the Question "How long does it take to scan and service the device, given a clocking rate of 8 MHz?"

Answer:

  • It takes [tex]4.5*10^{-6}sec[/tex] to scan and service the device

From the question we are told

A microprocessor scans the status of an output I/O device every 20 ms. This is accomplished by means of a timer alerting the processor every 20 ms.  

since,

[tex]Frequency = 8Mhz\\\\Time period will be = \frac{1}{8}*10^{-6}\\\\= 1.25*10^{-7}[/tex]

Instruction cycle = 12cycles

Therefore, each instruction will take

[tex]12 * \frac{1}{8}*10^{-6}\\\\= 1.5*10^{-6}[/tex]

Total time

[tex]= 3 * 1.5*10^{-6}\\\\= 4.5*10^{-6}sec[/tex]

For more information on this visit

https://brainly.com/question/23379286