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Exam zone


Intro to AVR ATtiny2313

CS423 Dick Steflik


AVR ATtiny2313


2313 Features 

RISC, 120 instructions, most executable in one clock cycle, 32x8 general purpose registers, up to 20 MIPS at 20 Mhz Memory - 2Kbytes Flash, 128 Bytes EEPROM, 128 bytes SRAM Peripherals Features – 1-8bit timer, 1- 16 bit timer, 4- PWM channels, On-chip analog comparitor, watchdog timer, Universal Serial Interface, Full Duplex USART

18 programmable I/O lines

Operating Voltage – 2.7 – 5.5VDC

In System Programmable via SPI (Serial Peripheral Interface)‫‏‬


Basic Pin Descriptions 

VCC – Digital Supply Voltage

Gnd – ground

Port A (PA2..PA0) – 3 bit, bi-directional I/O with selectable internal pullups

Port B (PB7..PB0) – 8 bit, bi-directional I/O with selectable internal pullups

Port D (PD6-PD0) - 7 bit, bi-directional I/O with selectable internal pullups

Reset – system reset – active low

XTAL1 – external crystal input (alt. PA0)‫‏‬

XTAL2 – external crystal output (alt. PA1)‫‏‬


Serial Peripheral Interface Bus 

SPI is used by all Atmel microcontrollers for loading the flash program memory (many other OEMs also)‫‏‬

Easily implemented in hardware

Faster than other methods (I2C, SMBUS)‫‏‬

Master-slave methodology

Half or Full Duplex operation


SPI with 2 slaves SPI Master

SPI Slave 1

SCLK MOSI

SCLK MOSI

MISO

MISO

SS1

SS

SS2 SPI Slave 2 SCLK MOSI MISO SS


AVR Programming AVR Programmer

PC

AVRDUDE PPT RS232 USB

ATtiny2313

VCC SCLK MOSI

VCC (20)‫‏‬ SCLK (19)‫‏‬

MISO

MISO (18)‫‏‬

GND

RESET (1)‫‏‬ GND (10)‫‏‬

MOSI (17)‫‏‬

GND


API Applications 

Flash, EEPROM, MMC and SD cards

Sensors

 

Temperature

Pressure (touch screens)‫‏‬

LCD Panels Communications (802.15 (ZigBee), CAN, Ethernet....)‫‏‬ Control – D/A, A/D, Digital Pots, position encoders


/* Blinker Demo */ /* Include useful pre-defined functions */ #include <avr/interrupt.h> // Defines pins, ports, etc to make programs easier to read #define F_CPU 100000UL // Sets up the default speed for delay.h #include <util/delay.h> int main(){ DDRD = _BV(PD4); while(1){ PORTD = _BV(PD4); _delay_ms(1000); PORTD &= ~_BV(PD4); _delay_ms(1000); } return(0); }

/* enable output on port D, pin 4 */


Interrupts 1 0x0000 BOR,Watchdog Reset 2 0x0001 0 3 0x0002 1 4 0x0003 Event 5 0x0004 Match A 6 0x0005 7 0x0006 8 0x0007 complete 9 0x0008 Empty 10 0x0009 Complete 11 0x000A 12 0x000B 13 0x000C Match B 14 0x000D Match A

Reset

External Pin, POR,

INT0

External Interrupt Request

INT1

External Interrupt Request

TIMER1 CAPT

Timer/Counter1 Capture

TIMER1 COMPA

Timer/Counter1 Compare

TIMER1 OVF TIMER0 OVF USART0,RX

Timer/Counter1 Overflow Timer/Counter0 Overflow USART0 Receive

USART0 UDRE

USART0 Data Register

USART0 RX

USART0 Transmit

ANALOG COMP PCINT TIMER1 COMPB

Analog Comparitor Pin Change Interrupt Timer/Counter1 Compare

TIMER0 COMPA

Timer/Counter0 Compare


ISR Macro  

#include <avr/interrupt.h> Defines the beginning of your Interrupt Servicing Routine 

Places the starting address of the ISR code into the interrupt vector ISR(SIG_INT0)‫‏‬ { cli(); //disable interrupts . . . sei(); // enable interrupts } places address of the body if the ISR into 0x0001


Programmable Interrupts 

INT0 - Pin 6

INT1 – Pin 7

PCINT – Pins 12-19

PCMSK – Pin Change Mask Register 

Which pins contribute to the pin change interrupt 

4 different pin changes can be detected    

Pin goes low Any logical change Falling edge Rising edge


Interrupt Sense Control Interrupt 1 Sense Control ISC11 ISC10 Description 0 0 0 1 1 0 1 1

Low level on INT1 Any logical change on INT1 Falling edge on INT1 Rising Edge on INT1

Interrupt 0 Sense Control ISC01 ISC00 Description 0 0 0 1 on INT0 1 0 1 1 INT0

Low level on INT0 Any logical change Falling edge on INT0 Rising Edge on


MCU Control Register 

Defines which of the four states will activate the interrupt

ex. MCUCR = (1<<ISC01) | (1<<ISC00)‫‏‬ Interrupt on pin INT0 falling edge


Example #include <avr/interrupt.h> int main(void)‫‏‬ { // set Pin 6 (PD02) as the interrupt pin PCMSK |= (1<<PIND2); // interrupt on INT0 falling edge MCUCR = (1<<ISC01) | (1 << ISC00); // turn on interrupts GIMSK |= (1<<INT0); // wait for interrupt while (1) { ... };


embedded sys2  

Exam zone Intro to AVR ATtiny2313 CS423 Dick Steflik AVR ATtiny2313 Operating Voltage – 2.7 – 5.5VDC 18 programmable I/O lines In System Pro...

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