Quelltext der Seite Arduino/Arduino2AVR

= Arduino -> AVR HOWTO =

This is an (incomplete) guide to how to map from Arduino source code to avr-gcc source code.
It's been written to map this this direction, but can be used to understand how to go the other direction as well.

== Step 1: Setup project ==

* Copy Makefile from some other project
** NB! Make sure DEVICE and SERIAL are correctly set
* Copy the <MyProject.pde> file to main.cpp

== Step 2: Edit main.cpp ==

 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
 #include <avr/interrupt.h>
 #include <avr/io.h>
 #include <util/delay.h>
 
 <insert .pde code here>
 
 int main(void)
 {
   cli();
 
   // set a2d reference to AVCC (5 volts)
   ADMUX &= ~(1<<REFS1);
 	ADMUX |= (1<<REFS0);
 
 	// set a2d prescale factor to 128
 	// 16 MHz / 128 = 125 KHz, inside the desired 50-200 KHz range.
 	// FIXME: this will not work properly for other clock speeds, and
 	// this code should use F_CPU to determine the prescale factor.
   ADCSRA |= (1<<ADPS2)|(1<<ADPS1)|(1<<ADPS0)|
   // enable a2d conversions
   (1<<ADEN);
 
   setup();
   sei();
 
   while (1) {
     loop();
   }
 		
   return 0;
 }

== Step 3: Port code away from Arduino ==

{||style="width:100%" border="1"
|- style="background-color:#aabbaa"
! Arduino || AVR || Notes
|- 
| byte                       || uint8_t
|-
| Serial.begin(<baud>)       || uart_init(<baud>)
|-
| Serial.print*()            || printf()
|-
| Serial.available()         || getchar() || NB! blocking
|-
| pinMode(pin, INPUT)        || DDRx &= ~_BV(bit); || | // For I/O pins, convert pin to port+bit
|-
| pinMode(pin, OUTPUT)       || DDRx &#124;= _BV(bit);
|-
| digitalWrite(pin, LOW)     || PORTx &= ~_BV(bit);
|-
| digitalWrite(pin, HIGH)    || PORTx &#124;= _BV(bit);
|-
| digitalRead(pin)           || (PINx & _BV(bit)) >> bit;
|-
| delay(ms)                  || _delay_ms(ms) || max delay is 262.14 ms / F_CPU in MHz. (16Mhz -> 16 ms)
|-
| delayMicroseconds(us)      || _delay_us(us) ||  max delay is 768 us / F_CPU in MHz. (16Mhz -> 48 us)
|-
| millis()                   || || Must be rewritten or implemented using a timer
|}

== Misc. Notes ==

Address of I/O register: _SFR_IO_ADDR(PORTB)
 (e.g. #define _SFR_IO_ADDR(sfr) (sfr - 0x20))

Read contents of I/O register: _SFR_IO8(register) // register = 00-3f
 (e.g. #define PORTB _SFR_IO8(0x18))
       #define _SFR_IO8(io_addr) (io_addr + 0x20)

=== Arduino pins to AVR port+bit ===

{|
| digital
|-
| 0  ||  PORTD,0
|-
| 1  ||  PORTD,1
|-
| 2  ||  PORTD,2
|-
| 3  ||  PORTD,3
|-
| 4  ||  PORTD,4
|-
| 5  ||  PORTD,5
|-
| 6  ||  PORTD,6
|-
| 7  ||  PORTD,7
|-
| 8  ||  PORTB,0
|-
| 9  ||  PORTB,1
|-
| 10 ||  PORTB,2
|-
| 11 ||  PORTB,3
|-
| 12 ||  PORTB,4
|-
| 13 ||  PORTB,5
|-
| analog
|-
| 0  ||  PORTC,0
|-
| 1  ||  PORTC,1
|-
| 2  ||  PORTC,2
|-
| 3  ||  PORTC,3
|-
| 4  ||  PORTC,4
|-
| 5  ||  PORTC,5
|}


[[Kategorie:Projekte]]
[[Kategorie:Arduino]]