3) a) Write a code for creating a square wave of 25% duty cycle on bit 3 of part 1.

b) Write a code for creating a square wave of 99% duty cycle on bit 7 of part 2.

1. Program 25% duty cycle on bit 3 of port 1.

.INCLUDE "M32DEF.INC"

LDI R20, HIGH(RAMEND)

OUT SPH, R20

LDI R20, LOW(RAMEND)

OUT SPL, R20 ;initialize stack pointer

SBI DDRC, 3 ;set bit 3 of DDRC (PC3 = out)

HERE: SBI PORT1, 3 ;set to HIGH PC3 (PC3 = 1)

CALL DELAY ;call the delay subroutine

CALL DELAY ;call the delay subroutine

CALL DELAY ;call the delay subroutine

CALL DELAY ;call the delay subroutine

CBI PORT1, 3 ;PC3 = 0

CALL DELAY ;call the delay subroutine

2. The program if 99% duty cycle on bit 7 of port 2.

.INCLUDE "M32DEF.INC"

LDI R20, HIGH(RAMEND)

OUT SPH, R20

LDI R20, LOW(RAMEND)

OUT SPL, R20 ;initialize stack pointer

SBI DDRC, 7 ;set bit 7 of DDRC (PC7 = out)

HERE: SBI PORT2, 7 ;set to HIGH PC7 (PC7 = 1)

CALL DELAY ;call the delay subroutine

CALL DELAY ;call the delay subroutine

CALL DELAY ;call the delay subroutine

CALL DELAY ;call the delay subroutine

CALL DELAY ;call the delay subroutine

CBI PORT2, 7 ;PC7 = 0

RJMP HERE ;keep doing it

Step-by-step explanation

1. The 25% duty cycle means that the ON state will only toggle every 25% duty cyle of set time. and the rest 75% will be in OFF state. The program will set the pc3 ON every 25% and OFF every 75% of duty cycle.

2. The 99% cycle means that the

almost duty cycle will be in ON state.