ECET 330 DeVry Final Exam

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PORTB = PORTB & 0x0F;
Question 8.8.(TCO 8) The following program creates square wave pulses on PB0. What is the duty cycle?
ORG $8000 LDS #$4000 LDAA #$FF STAA DDRB BACK BSET PORTB,%00000001 JSR DELAY JSR DELAY BCLR
PORTB,%00000001 JSR DELAY JSR DELAY BRA BACK (Points : 8)
o 75%
o 66%
o 50%
o 25%
Question 9.9.(TCO 8) Find the value for PORTB after the execution of the following code: PORTB = 0x55 ^ 0xFF;
(Points : 8)
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PORTB = 0x05
PORTB = 0x0A
PORTB = 0xAA
PORTB = 0xFF
Question 10.10.(TCO 8) Fill in the blank to get 0x38 on PORTB. unsigned char BCD_Byte = 0x89; unsigned char
x; x = BCD_Byte & 0xF0; _____; PORTB = x | 0x30; (Points : 8)
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x=x>>4;
x=x>>2;
x=x