The document discusses the Atmega32 microcontroller. It has 32 KB of program memory and 32 programmable I/O pins across four ports (PORTA-PORTD). Each port is controlled by data direction, output, and input registers (DDRx, PORTx, PINx). The document explains how to configure the registers to set pin directions and write/read pin values. It also covers delays, buttons, and using internal pull-up resistors.

1. AVR
Microcontroller
© 2019 by Mahmoud Amr

3. family of AVR microcontrollers

4. Atmega32
• At  atmel (company)
• Mega  mega avr
• 32  is refer to the size of program
memory (flash ) in the atmega32 (32Kbyte) .

5. features of Atmega32

6. 8-Bit AVR General Purpose Registers
at page 11 in datasheet

7. The X-register, Y-register, and Z-register
• as the X-, Y-, and Z-pointer registers can be set to index any
register in the file
The registers R26…R31 have some added functions to their general purpose usage.
These registers are 16-bit address pointers for indirect addressing of the data
space. The three indirect address registers X, Y, and Z are defined as described in
the figure.

9. I/O PORTS
Dio ports digital input output ports
GPIO ports  general purpose input output ports
I/O PORTS  input / output ports

10.  32 Programmable I/O pins.
PORT A (PA7..PA0)
PORT B (PB7..PB0)
PORT C (PC7..PC0)
PORT D (PD7..PD0)
 Each PORT is controlled by 3 registers:
1. DDRx (Data Direction Register)
2. PORTx (Output Register)
3. PINx (Input Register)
NOTE: The Directions of each I/O lines must be
configured (input or output) before they are used .

11. PORT is controlled by 3 registers

12. Decided which input and which output
To use I/O ports in ATMEGA32
(PORTx/PINx/DDRx) we need to include header
file <avr/io.h>
1- Configure the port direction use register DDRX
• 1 for Output.
• 0 for Input.
2- In Read(input case) : Use register PINx.
3- In Write(output case) : Use register PORTx.

13. set values in registers DIO
• DDRA=5; /*(decimal)mean I activate pin 0 and
pin 2 as output and the rest as
input pins */
• DDRB=0x14; /*(hexadecimal)mean I activate pin
2 and pin 4 as output and the rest
as input pins */
• DDRC=0b00000011; /*(binary)mean I activate pin 0 and
pin 1 as output pins and the rest
as input pins */
• deal with a specific one pin

14. deal with a specific one pin
• Make OR operation on the register with The pin number
– For example if we want to set pin number 5 in PORTA
» PORTA = PORTA | (1<<5);
-To set specified bit in register (1)
1000 1000
| OR
0001 0000
--------------
1001 1000
1001 1000
| OR
0001 0000
--------------
1001 1000

15. • Make AND operation on the register with (NOT) The pin number.
– For example if we want to set pin number 3 in PORTB
» PORTB = PORTB & ( ~(1<<3) );
-To clear specified bit in register
1000 1100
& AND
1111 1011
--------------
1000 1000
1000 1000
& AND
1111 1011
--------------
1000 1000
0000 0100
~ NOT
--------------
1111 1011

16. • Make XOR operation on the register with The pin
number
– for example if we want to toggle pin number 2 in PORTC
» PORTC = PORTC ^ (1<<PC2);
- To toggle specified bit in register

17. DDRx
Configure the port direction use register DDRX
1 for Output.
0 for Input.
DDRA=0xFF; //initialize portA as output
DDRB=0x00; //initialize portB as input

18. PORTx
When I need to Write data as 0 0V , 1  5V .
- set DDRx as output
PORTA=0xFF; //ALL portA are output 5V
PORTA=0x00; //ALL portA are output 0V

19. PINx
When I need to Write data as 0 0V , 1  5V .
- set DDRx as input
X = PINA; //PORTA as input and data save in X

21. • To use the delay feature, we need to include
header file <util/delay.h> and write before it
# define F_CPU 8000000ul to achieve the
required delay .
– _delay_ms(1000); //Delay 1000 ms = 1 second.
– _delay_ms(100); //Delay 100 ms.

22. Buttons
• Pushbutton
1- pull-up mode
2- pull-down mode
Button V out
No push 5 V
Push 0 V
Button V out
No Push 0 V
Push 5 V

23.  Note in case you set any PIN as input you can activate the internal pull up
resistor by setting the corresponding bit in PORTX register.
Example
To set the pin 2 in PORTB as input pin and use the internal pull up
resistor of this pin.
DDRB = DDRB & (~(1<<PB2));
PORTB= PORTB | (1<<PB2);