Provide answers for the next exercises assuming a DS89C450 based system: 1. A Fi

Question

Provide answers for the next exercises assuming a DS89C450 based system:

1. A Find the clock frequency if the machine cycle time is 110nS

2. Find the machine cycle time if the crystal frequency is 13MHz

3. Find the machine cycle time if the crystal frequency is 9MHz

4. Find the time delay for the following delay subroutine below if the clock frequency is 11.0592MHz

delay

mov

r2, #100

again:

mov

r3, #200

here:

nop

nop

nop

djnz

r3, here

djnz

r2, again

ret

delay

mov

r2, #100

again:

mov

r3, #200

here:

nop

nop

nop

djnz

r3, here

djnz

r2, again

ret

Explanation / Answer

1)

f=1/time period = 1/110 ns = 9.09 Mhz

2)

T=1/f = 1/13Mhz = 76.92 ns

3)

T=1/f = 1/9 Mhz = 111.11 ns

4)

frequency = 11.0592 Mhz

T = 1/f = 90.42 ns

So basically a clock period is of 90.42 ns

so the delay as per code is of 100 units = 90.42 * 100 = 9042 ns

Related Questions

Navigate

• Browse (All)
• Browse P
• Subjects

---

---

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.