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ATtiny_x313.md

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ATtiny 2313/4313

x4 pin mapping

Specifications .
Flash (program memory) 2048b/4096b
RAM 128/256 bytes
EEPROM 128/256 bytes
Bootloader No
GPIO Pins 17
ADC Channels None
PWM Channels 4
Interfaces UART, USI
Clock options Internal 0.5/1/4/8 MHz, external crystal or clock* up to 20 MHz
  • Manual steps required. See notes in README under "Using external CLOCK (not crystal).

Tone Support

Tone() uses Timer1. For best results, use pin 12, and 13, as this will use the hardware output compare to generate the square wave instead of using interrupts. In order to use Tone(), you must select Initialize Secondard Timers: Yes

Initialize Secondard Timers option

When an Arduino sketch runs, prior to Setup() being called, a hidden init() function is called to set up the hardware. One of the things it does is configure the timers. Timer0 (used for millis) is always configured, but on the x313 series, due to the extremely limited flash, it is optional whether to initialize Timer1. If Timer1 is not initialized, Tone() and PWM on pins 12 and 13 will not work.

I2C Support

There is no hardware I2C peripheral. I2C functionality can be achieved with the hardware USI. As of version 1.1.3 this is handled transparently via the special version of the Wire library included with this core. You must have external pullup resistors installed in order for I2C functionality to work at all.

SPI Support

There is no hardware SPI peripheral. SPI functionality can be achieved with the hardware USI - as of version 1.1.3 of this core, this should be handled transparently via the SPI library. Take care to note that the USI does not have MISO/MOSI, it has DI/DO; when operating in master mode, DI is MISO, and DO is MOSI. When operating in slave mode, DI is MOSI and DO is MISO. The #defines for MISO and MOSI assume master mode (as this is much more common).

UART (Serial) Support

There is one full hardware Serial port, named Serial. It works the same as Serial on any normal Arduino - it is not a software implementation. Be aware that due to the limited memory on these chips the buffers are quite small.

To use only TX or only RX channel, after Serial.begin(), one of the following commands will disable the TX or RX channels

UCSRB &=~(1<<TXEN); // disable TX
UCSRB &=~(1<<RXEN); // disable RX

There is no ADC

Interrupt Vectors

This table lists all of the interrupt vectors available on the ATtiny x313-family, as well as the name you refer to them as when using the ISR() macro. Be aware that a non-existent vector is just a "warning" not an "error" - however, when that interrupt is triggered, the device will (at best) immediately reset - and not cleanly either. The catastrophic nature of the failure often makes debugging challenging. Vector addresses are "word addressed". vect_num is the number you are shown in the event of a duplicate vector error, among other things.

vect_num Vector Address Vector Name Interrupt Definition
0 0x0000 RESET_vect Any reset (pin, WDT, power-on, BOD)
1 0x0001 INT0_vect External Interrupt Request 0
2 0x0002 INT1_vect External Interrupt Request 1
3 0x0003 TIMER1_CAPT_vect Timer/Counter1 Capture Event
4 0x0004 TIMER1_COMPA_vect Timer/Counter1 Compare Match A
5 0x0005 TIMER1_OVF_vect Timer/Counter1 Overflow
6 0x0006 TIMER0_OVF_vect Timer/Counter0 Overflow
7 0x0007 USART0_RX_vect USART0 Rx Complete
7 0x0007 USART_RX_vect Alias - provided by io.h
8 0x0008 USART0_UDRE_vect USART0 Data Register Empty
8 0x0008 USART_UDRE_vect Alias - provided by io.h
9 0x0009 USART0_TX_vect USART0 Tx Complete
9 0x0009 USART_TX_vect Alias - provided by io.h
10 0x000A ANALOG_COMP_vect Analog Comparator
11 0x000B PCINT0_vect Pin Change Interrupt 0 (PORT B)
19 0x000B PCINT_B_vect Alias - provided by io.h
12 0x000C TIMER1_COMPB_vect Timer/Counter1 Compare Match B
13 0x000D TIMER0_COMPA_vect Timer/Counter0 Compare Match A
14 0x000E TIMER0_COMPB_vect Timer/Counter0 Compare Match B
15 0x000F USI_START_vect USI Start Condition
16 0x0010 USI_OVERFLOW_vect USI Overflow
17 0x0011 EE_READY_vect EEPROM Ready
18 0x0012 WDT_OVERFLOW_vect Watchdog Time-out (interrupt mode)
19 0x0013 PCINT1_vect Pin Change Interrupt 1 (PORT A) *
19 0x0013 PCINT_A_vect Alias - provided by io.h
20 0x0014 PCINT2_vect Pin Change Interrupt 2 (PORT D) *
20 0x0014 PCINT_D_vect Alias - provided by io.h
This core always compiles with ATtiny2313a, not ATtiny2313 as the target
  • Vector not available in ATtiny2313 (although it is defined in the io headers!)