Attiny2313

ATtiny 2313

Memo fact sheet

• Code : 2048 Bytes / EEPROM : 128 Bytes / RAM : 128 Bytes
• It has no Analog to Digital Converter, but the AIN1/AIN0 pair is an analog comparator
• Homepage https://www.microchip.com/en-us/product/ATtiny2313A#

Projects using Attiny2313

Pin Layout

ATMEL ATTINY2313
                       +-\/-+
      RESET      PA2  1|    |29  VCC
      RX   (D 0) PD0  2|    |19  PB7 (D 16)(SCK)
      TX   (D 1) PD1  3|    |18  PB6 (D 15)(MISO)
           (D 2) PA1  4|    |17  PB5 (D 14)(MOSI)
           (D 3) PA0  5|    |16  PB4 (D 13) (PWM OC1B)
      INT0 (D 4) PD2  6|    |15  PB3 (D 12) (PWM OC1A)
      INT1 (D 5) PD3  7|    |14  PB2 (D 11) (PWM OC0A)
           (D 6) PD4  8|    |13  PB1 (D 10) (AIN1) [Comparator-]
 (PWM OC0B)(D 7) PD5  9|    |12  PB0 (D 9) (AIN0)  [Comparator+]
                 GND 10|    |11  PD6 (D 8)
                       +----+

Pin configuration

Alternate development tool : WinAVR

• http://www.chip45.com/info/Portable-WinAVR.html
• http://winavr.sourceforge.net/index.html Check the portable version if you don't feel like installing it, works very fine. Editor is so-so but ok, I'm too much used to professional tools (spoiled by everyday job)

Programmer

• Doc http://www.pololu.com/catalog/product/1300
• You must have XP SP3. Installing it was not an quick task (it's veeeeeeery long) but worked fine in the end. Didn't worked with SP2, works very fine with SP3, I tried.
• You must use a single digit COM port (force it in case). Note that I didn't had problem but just followed the documentation.
• Tou must provide the micro chip with a good 5V if you don't want to brick it. A triple AA cells pack is NOT sufficient, just use your PC USB solid 5V.
• Use communication speed of 200 KHz (default setting) that's waaaaay sufficient to upload the maximum 2048 bytes of your program in the blink of an eye (or so).
• Tips for uploading code from Sparkfun tutorials http://www.sparkfun.com/commerce/tutorial_info.php?tutorials_id=142

Things to know when programming your ATtiny 2313

• If you don't use a crystal (often the case with this small chip), you use the internal 8 MHz +/- 10% oscillator which is the factory settings, and it's cool. But by default it use factor 8 speed divider and runs at 1MHz which is not cool. So just tell the chip to be a good boy and not downscale.

    //factor settings is to divide internal clock 8MHz by 8.
    //don't, and just run at 8 MHz (set the clock divider to 1 so no effect)
    CLKPR = (1<<CLKPCE);
    CLKPR = 0; // Divide by 1 

Sample codes

Timer interrupt

• http://www.avrfreaks.net/index.php?name=PNphpBB2&file=viewtopic&p=216769
• http://paste.factorcode.org/paste?id=358
• http://www.daqq.eu/index.php?show=prj_sanity_nullifier
• http://pichonjulien.blogspot.com/2009/10/pwm-avec-un-attiny2313.html

//
// test of timed interrupt on attiny 2313
 AlanFromJapan http:kalshagar.wikispaces.com/
//
// Inspirations :
 http:cappels.org/dproj/1_kHz_Signal_Source/1_KHz_Sine_Wave_Generator.html
 http:www.daqq.eu/index.php?show=prj_sanity_nullifier
 http:pichonjulien.blogspot.com/2009/10/pwm-avec-un-attiny2313.html
//
 
// includes
#include 
#include 
#include 
 
//use this trick to ""adjust"" the timer1 and subscale it
#define TIMER_DIVIDER 1
volatile uint16_t mTimerCounter = 0;
 
ISR(TIMER1_OVF_vect){
    mTimerCounter%20%20;
 
    if (mTimerCounter >= TIMER_DIVIDER){
        //first thing, reset
        mTimerCounter = 0;
        //then do the interrupt job
 
        //blink B1
        PORTB ^= 0x02;
    }
}
 
//inits timer 1 to do interrupt on overflow (calls ISR(TIMER1_OVF_vect))
void init_timer1_OVF() {
    //timer 1 prescaler : makes clock / 64  -> tick every 1/4 sec roughly
    TCCR1B=0x03;
    //trigger the interrupt vector TIMER1_OVF_vect when timer 1 is overflow
    TIMSK = 0x80;
 
    //sets the interruptions to enabled
    sei();
}
 
 
//Inits timer 0 to do PWM on pin B2
void init_timer0_PWM()
{
    /* Set Fast PWM mode. */
    TCCR0A |= (1<<WGM00) | (1<<WGM01);
 
    /* Clear 0C0A on compare. */
    TCCR0A |= (1<<COM0A1);
 
    /* Start timer, no prescaling. */
    TCCR0B |= (1<<CS00);
 
    /* Duty cycle 0% */
    OCR0A = 0;
}
 
 
//
// main function
//
void main(void) {
 
    //factory settings is to divide internal clock 8MHz by 8.
    //don't, and just run at 8 MHz (set the clock divider to 1 so no effect)
    CLKPR = (1<<CLKPCE);
    CLKPR = 0; // Divide by 1 
 
    //all ports of bank B goes output PB6~0 is output
    DDRB = 0xFF;
 
    //will be used to re-divide the TIMER0 (too fast)
    mTimerCounter = 0;
 
    //init for PWM
    init_timer0_PWM();
    //init for timer interrupt
    init_timer1_OVF();
 
    while (1){
        //Blink B0 on or off
        PORTB ^= 0x01;
 
        //pulse led on B3
        unsigned char i ;
        for(i=0; i < 255; i%20%20) {
            OCR0A = i;
            _delay_ms(10);
        }
 
        for(i=255; i > 0; i--) {
            OCR0A = i;
            _delay_ms(10);
        }        
        OCR0A = 0;
 
 
        _delay_ms(300);
    }
 
}
 
 
////////////////////////////////////////////////////////////

PWM with ATTiny2313

#include 
#include 
#include 
#include 
 
#define    F_CPU    1000000UL
#include 
 
void init_timer(){
/* Set Fast PWM mode. */
TCCR0A |= (1<<WGM00) | (1<<WGM01);
/* Clear 0C0A on compare. */
TCCR0A |= (1<<COM0A1);
/* Start timer, no prescaling. */
TCCR0B |= (1<<CS00);
/* Duty cycle 0% */
OCR0A = 0;
}
 
void init_led(){
DDRB |= (1<<PB2);
}
 
int main(int argc, char *argv[]){
int i;
 
init_led();
init_timer();
 
while(1) {
  for(i=0; i < 255; i%20%20) {
      OCR0A = i;
      _delay_ms(10);
  }
 
  for(i=255; i > 0; i--) {
      OCR0A = i;
      _delay_ms(10);
  }
}
 
return 0;
}

Basic sample : interrupt comparator hello world on attiny2313

//Minimal sample of Comparator interrupt on attiny2313
// includes
#include 
#include 
#include 
 
 
//B3 is 0x08 = b00001000
void test_blinkB3(){
    PORTB ^= 0x08; //led on
    _delay_ms(50);
    PORTB ^= 0x08; // led off
}
 
 
//B2 is 0x04 = b00000100
void test_blinkB2(){
    PORTB ^= 0x04; //led on
    _delay_ms(100);
    PORTB ^= 0x04; // led off
}
 
//Interrupt code of the comparator
// Our settings is interrupt on rising edge. Meaning no 2 consequent interrupt if stays high. It is rose when comparator output goes from 0 to 1 only.
// NB  : AIN0 is POSITIVE pin, AIN1 is NEGATIVE pin
// NB2 : you need to stabilize the power rail with a capacitor (otherwise you'll have ripples and misreading). With AIN1=Comp-=0v a 200uF is fine.
ISR(ANA_COMP_vect) {
 
    //with this test, ensure that indeed the interrupt result is 1 = V(AIN0) > V(AIN1)
    //(double check ?)
    if ( (ACSR & (1 << ACO)) != 0 ) {
        test_blinkB2();    
    }
}
 
//
// main function
//
int main(void) {
    //factory settings is to divide internal clock 8MHz by 8.
    //don't, and just run at 8 MHz (set the clock divider to 1 so no effect)
    CLKPR = (1<<CLKPCE);
    CLKPR = 0; // Divide by 1 
 
    //port B pins 7-2 go output, 1-0 go input(it's the comparator)
    DDRB = 0xFC;
 
    //needed it seems. 
    //One need also a pulldown on the AIN0 (Comparator%20) to avoid having it floating (if you use a switch for instance)
    PORTB &= ~(1<<PB0);    // no Pull-up on PB0
 
    ACSR  |=  (1<<ACI);    // clear Analog Comparator interrupt
    ACSR  |=
        (0<<ACD)   |         // Comparator ON
        (0<<ACBG)  |         // Disconnect 1.23V reference from AIN0 (use AIN0 and AIN1 pins)
        (1<<ACIE)  |         // Comparator Interrupt enabled
        (0<<ACIC)  |         // input capture disabled
        (1<<ACIS1) |         // set interrupt bit on rising edge
        (1<<ACIS0);          //    (ACIS1 and ACIS0 == 11)
 
 
    sei();                 // enable global interrupts
 
    while (1) {/*all the job is done in the interrupt */
        // a little "is alive" debug trick that blink another led every second or so
        test_blinkB3(); _delay_ms(1000);
    }
}
 

I2C TWI

As a master

• ATtiny2313 use USI not pure internal TWI, so can't wake on TWI interrupt
• ATtiny2313 must then use the USI_I2C library which works just fine out of the box

As a slave

• The library to use http://playground.arduino.cc/Code/USIi2c
• A working sample http://pastebin.com/96emhzKi

• you can skip the external pullups if you use Attiny's internals
• don't forget to call sei(); after initializing the USI client ! (did cost me 4 hours that one stupid miss)

Infrared

With Arduino IDE

• Use with ARDUINO IDE (drop it, compiler is not optimized enough, should use WinAVR)
  • http://www-ice.yamagata-cit.ac.jp/ken/senshu/sitedev/index.php?AVR%2Fnews46#u4db8215
  • http://d.hatena.ne.jp/OGURAM/20091013/1255393597
  • http://d.hatena.ne.jp/OGURAM/20091012
  • http://www.arduino.cc/cgi-bin/yabb2/YaBB.pl?num=1189970096/6
  • http://www.arduino.cc/cgi-bin/yabb2/YaBB.pl?num=1247267779
  • http://www.arduino.cc/cgi-bin/yabb2/YaBB.pl?num=1236434254/52#52

Core

Boards.txt

##############################################################
attiny2313.name=My Arduino w/ ATTINY2313
attiny2313.upload.protocol=hidspx,-d1
attiny2313.upload.maximum_size=2048
attiny2313.upload.speed=19200
attiny2313.bootloader.low_fuses=0xe4
attiny2313.bootloader.high_fuses=0x9d
attiny2313.bootloader.extended_fuses=0xff
attiny2313.bootloader.path=attiny2313
attiny2313.bootloader.unlock_bits=0xFF
attiny2313.bootloader.lock_bits=0xCF
attiny2313.build.mcu=attiny2313
attiny2313.build.f_cpu=8000000L
attiny2313.build.core=attiny2313