COMSATS UNIVERSITY ISLAMABAD
MICROPROCESSOR SYSTEMS AND INTERFACING
LAB REPORT 4
SUBMITTED TO:
SIR KHIYAM
IFTIKHAR
SUBMITTED BY:
JUNAID AHMAD
Ibrar ahmad
Jarrar malik
REGISTRATION NO:
CIIT/FA19-BEE-089/ISB
Ciit/fa19-bee-083/isb
Ciit/fa19-bee-087/isb
DATE:
15-10-2021
Introduction to
Assembly Language Programming of AVR Microcontrollers
Objectives:
· To
get started with assembly language programming for AVR microcontrollers.
· Implementing loops and
conditional execution instructions in Assembly language
Required Tools:
Software Tools:
· AVR
Studio/ Microchip Studio
·
Proteus ISIS
· AVRDUDESS
Hardware Tools:
· Arduino
Nano
· Oscilloscope
· Resistors
470 Ω
· LED
· Wires
In-Lab:
Task 1:
Generate a square wave signal of frequency 1 KHz and 40%
duty cycle on a digital I/O pin of ATmega328P.
Steps:
1: Initialize stack pointer.
2: Configure Pin 0 of Port B as output.
3: Send 1 on PB0.
5: Call Delay of 400us.
6: Send 0 on PB0.
7: Call delay of 600us.
8: Repeat forever
Code:
.include "m328Pdef.inc"
;Initialize stack
pointer.
ldi r16,HIGH(RAMEND)
out SPH, R16
ldi r16,LOW(RAMEND)
out SPL, R16
start:
ldi r16,0x01 ;load 0x01 into a register r16
out DDRB,r16 ;configure PB0 as output: DDRB=0x01
forever:
ldi r19,0x01 ;load 0x01 into a register
out PORTB,r19 ;PB0=1
rcall delay_16ms
ldi r19,0x00
out PORTB,r19 ;PORTB=0x00
rcall delay_600us
rjmp forever ;keep doing this forever
delay_16ms: ;This subroutine will call delay of 100us
4 times
;to generate a delay of 400us
ldi r20,20
loop1:
rcall delay_100us
dec r20
brne loop1
ret
delay_600us: ;This subroutine will call delay of 100us
6 times
;to generate a delay of 600us
ldi r20,6
loop2:
rcall delay_100us
dec r20
brne loop2
ret
delay_100us: ;This subroutine will generate a delay of
100us
; Inner loop
count =4 (Ignoring overhead)
; Delay =
(1/16M)*4*4*100
ldi r18, 225
l1: ldi r19,225
l2:
nop
dec r19
brne l2
dec r18
brne l1
ret
Simulation:
Hardware
task:
Task 2:
Write a program to toggle all bits of PORT D with
some delay (Specified by Lab Instructor). Simulate it on Proteus and implement
it on Hardware.
Steps:
1: Initialize stack pointer.
2: Make Port B an output port.
3: Load 0x55 in any general purpose register,
say R16.
4: Output R16 on Port B.
5: Call Delay.
6: Complement R16.
7: Repeat Forever
Code:
.include "m328Pdef.inc"
// lodaing
stack pointer
ldi r16, HIGH(RAMEND)
out sph, r16
ldi r16, LOW(RAMEND)
out spl, r16
// make
port B an output port
ldi r16, 0xFF
out DDRB, r16 // port b is
output
// load
0x55
ldi r16, 0x55
// output
r16 on port B
out PORTB, r16
// delay
call delay_200ms
// load
0xAA in
ldi r16, 0xAA
// output
r16 on port B
out PORTB, r16
delay_200ms:
ldi
R19,80 // 80*100*100*4*1/16MHz
outer_loop:
rcall
inner_loop
dec
R19
brne
outer_loop
inner_loop:
ldi
R17,100
label1:
ldi
R18,100
label2:
Nop
Dec R18
brne
label2
dec
R17
brne
label1
ret
Simulation:
post
lab task:
Blinking LED’s with different frequencies.
Description:
Connect 4 LED’s to PORT B of AT mega 328P.Using loops and
conditions write an assembly program that makes these LED blinks.
LED 0 should blink an ON/OFF time of 200ms
LED 1 should blink an ON/OFF time of 400ms
LED 2 should blink an ON/OFF time of
800ms LED 3 should blink an ON/OFF time of 1600ms
Simulate on proteus.
CODE:
.include "m328Pdef.inc"
ldi
r16,HIGH(RAMEND)
out SPH,
R16
ldi
r16,LOW(RAMEND)
out
SPL, R16
start:
ldi r16,0xff
out
DDRD,r16
forever:
ldi
r19,0xff
out
PORTD,r19
rcall
delay_200ms
ldi
r19,0xFE
out
PORTD,r19
rcall
delay_200ms
ldi
r19,0xFD
out
PORTD,r19
rcall
delay_200ms
ldi
r19,0xFC
out
PORTD,r19
rcall
delay_200ms
ldi
r19,0xFB
out
PORTD,r19
rcall
delay_200ms
ldi
r19,0xFA
out
PORTD,r19
rcall
delay_200ms
ldi
r19,0xF9
out
PORTD,r19
rcall
delay_200ms
ldi
r19,0xF8
out
PORTD,r19
rcall
delay_200ms
ldi
r19,0xF7
out
PORTD,r19
rcall
delay_200ms
ldi
r19,0xF6
out
PORTD,r19
rcall
delay_200ms
ldi
r19,0xF5
out
PORTD,r19
rcall
delay_200ms
ldi
r19,0xF4
out PORTD,r19
rcall
delay_200ms
ldi
r19,0xF3
out
PORTD,r19
rcall
delay_200ms
ldi
r19,0xF2
out
PORTD,r19
rcall
delay_200ms
ldi
r19,0xF1
out
PORTD,r19
rcall
delay_200ms
ldi
r19,0xF0
out
PORTD,r19
rcall
delay_200ms
rjmp
forever ;keep
doing this forever
delay_200ms : ;This
subroutine will call delay of 25ms 8 times
;to
generate a delay of 200ms
ldi
r21,8
loop2:
rcall
delay_25ms
dec r21
brne
loop2
ret
delay_25ms : ;This subroutine will call delay of 100us 250 times
;to
generate a delay of 25ms
ldi
r20,250
loop1:
rcall
delay_100us
dec r20
brne
loop1
ret
delay_100us:
;This subroutine will generate a delay of
100us
; Inner
loop count =4 (Ignoring overhead)
; Delay =
(1/16M)*4*4*100
ldi r18,
4
11: ldi r19,100
l2:
nop
dec r19
brne l2
dec r18
brne l1
ret
Simulation:
CRITICAL
ANAYSIS:
In this lab we studied about the time delay and their
calculation in AVR microcontrollers. We can either implement time delays by
manual calculations and keeping registers engaged or by using the delay.h
library for the microcontroller units.
In first task duty cycle of 40%
was generated by changing the delay time of outer and inner loop and afterwards
the output waves were observed on oscilloscope. In second task a delay of 200
milliseconds as instructed by the lab teacher was implemented and its effect was
observed on LEDs connected on Port D.
إرسال تعليق