(For those who not know hexazecimal : the numerating decimal is 0,1,2,....9 but hex numerating is 0,1,2,....9,A,B,C,D,E,F

mean that numer 10 decimal have 10 sign and 10 hexa have 16 sign...

E hexa =14 decimal

F hexa =15 decimal

10 hexa =16 decimal

11 hexa =17 decimal and go on

Hexa is represent by $sign ... so $11=17  and from now on we will use only hex numbers)

So at address 0 need to write :

00  rjmp $60       >>>rjmp  mean jmp at address

rjmp have menemonic $C0 .... mean that when processor receive number $C0 he knows that need to jump ... but where?...

The second number represent how many locations need to jump

So ... when processor receive $C02F ... he know that need to jump $2F locations

And now ... a little introducing about how processor read memory instructions:

The processor read 2 location , and execute ,after read another 2 location and execute...

But memory is organized as first bit is less important...that mean that processor read second number first and interpret as function

So ... if our command is $C02F that mean jump $2F locations (attention JUMP $2F LOCATIONS  not JUMP AT $2F LOCATION!!!)

Need to write $2FC0 because microprocessor begin read second location that is $C0 (jump)

So finally you can write $2FC0 that mean JUMP $2F LOCATIONS ...That mean after $2F location is address $60

Now at $60 address you can write your code!

First need to set register at OUT.

  8F EF        LDI r24, 0xFF

  84 B9        OUT 4, R24  

Now a little theory about registers.

The register is locations of another little memory(not memory program) 

and have a set of temporary register from 0 to 32 where can

be load data , the  processor work only with values stored in these registers , not directly...

and another set of register where contain information about periferics ( for example ports ,that is pins where can connect a led)

This pin can be input or output in function of what value contain these registers.

Any register have a specific function ...

For example $24 register control 8 pin (Portb)

So ... I can control PB0 to PB7 pins with $4 register

Now a little theory about binary numerotation ... If for hexa i adeed few extrasign A,B,C,D,E,F

Now for binary i use only two sign ... 0 and 1

Binary is represent by B

So 0 decimal=0 binar,1 decimal=1 binar,2 decimal=10 binar ... so in another words:

0B=0  ,  1B=1,   10B=2  , 11B=3

A register contain 8 little location where can write only 1 or 0

So ... my register $4 that control 8 out pin have 8 bit.

each bit controls a gate ... so if i write in $4  register B00000001  ... mean that i set PB0 as output

if i write B11111110  means that all PB1 to PB7 is as output but only PB0 is as input

0 is for input and 1 for output 

So... if i want command a led need to set port as output ... but if i want read a senzor need to set port as input!!!

So... if i put a led on PB0 and need to command it , need to set bit0 from $4 register 

Attention ... exist many type of register ... one that control peripheal , another can store data temporally ,ecc

So when want to write to register $20 for example , need to know wich register is , ecause $20 can be a location of memory, $20 can be temporary registers ,$20 can be input /output register 

So same name ... but different registers!!!

Now return to own program!

sa continui cand am timp ... am ramas sa caut tabela cu opcode ... si nu o gasesc!

PB5 ( D13 ) Led

Register

$4 DDRB

$5 PORTB

0000:

2FC0

00-$54 vector intrerupere

incepem cu $60

:$60

DDRB = 0xFF; //Nakes PORTC as Output

  8f ef        ldi r24, 0xFF

  84 b9        out 4, r24  

PORTB = 0xFF; //Turns ON All LEDs

  8f ef        ldi r24, 0xFF

  85 b9        out 5, r24     

-----------------------------------------------

PORTB = 0; //Turns OFF All LEDs

  80 e0        ldi r24, 0    

  85 b9        out 5, r24  

Many people try to understand how avr microcontrollers working!

And many for them ... think to modify or create programs in low mode.

For this i create this page to explain that is not easy, is a complicated mode.

So...i have blinking led.c file.For title you know what make it.

This file is write in c avr asm... that is low language possible known by all programmers...

but yet is not very low!

The low language is opcode (click here for see table of opcodes), is impossible working in this mode! The microprocessor can read only this numbers... so ... for this in arduino is load a hex file, language that microprocessor understand!

First try to load a mini program in arduino with minimal components.

The popular program is avrdude .

You need download these files in your folder that use for your test.

When you upload a file to microcontroller (arduino nano has a atmega32 microcontroller) , you can use avrdude for example for upload, will begin write by adress 0.

But in microcontroller memory begin with interrupts, that mean is allocates adress for type of interrupts and after this begin the code.Any type of microcontrollers have divers interrupts.

 for example the 

-----------------------------------------------------

arduino pins

arduino grbl

Arduino nano

0x03 PINB

0x04 DDRB

0x05 PORTB

0x06 PINC

0x07 DDRC

0x08 PORTC

0x09 PIND

0x0A DDRD

0x0B PORTD

        PB5 led onboard 

<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<

https://github.com/Protoneer/grbl-master

Grbl v0.8  v0.9

D8   PB0   stepper enable/disable

D7   PD7  direction Z

D6   PD6   direction Y

D5   PD5   direction X

D4   PD4   step Z

D3   PD3   step Y

D2   PD2   step X

<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<

test.bat  create hex from asm

avra test.asm

test1.bat upload to microcontroller

mode com3 BAUD=9600 PARITY=n DATA=8  

avrdude -p m328p -b 57600 -P com3 -c arduino -U flash:w:test.hex 

<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<

test.asm

.device ATmega32

.equ PORTD = 0x0B

.equ DDRD  = 0x0A

.equ PORTB = 0x05

.equ DDRB  = 0x04

.org 0x0000

    jmp main

.org 0x0060

main:

;PD5 grbl direction pin

;ldi r24, 1 ;PB0 enable x

;out DDRB,r24

;out PORTB,r24

ldi r24, 0b100100 ;PD5 direction x and PD2 step x

out DDRD,r24

loop:

ldi r24, 0b100000 ; STEP (PD2) HIGH

out PORTD,r24

      ldi  r18, 2

    ldi  r19, 160

    ldi  r20, 147

L1: dec  r20

    brne L1

    dec  r19

    brne L1

    dec  r18

ldi r24, 0 ; STEP (PD2) LOW

out PORTD,r24

  ldi  r18, 2

    ldi  r19, 160

    ldi  r20, 147

L1x: dec  r20

    brne L1x

    dec  r19

    brne L1x

    dec  r18

rjmp loop

<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<

AVR Delay Loop Calculator

http://www.bretmulvey.com/avrdelay.html

------------------------------------------------------

PB5 ( D13 ) Led

Register

$4 DDRB

$5 PORTB

0000:

2FC0

00-$54 vector intrerupere

incepem cu $60

:$60

DDRB = 0xFF; //Nakes PORTC as Output

  8f ef        ldi r24, 0xFF

  84 b9        out 4, r24  

PORTB = 0xFF; //Turns ON All LEDs

  8f ef        ldi r24, 0xFF

  85 b9        out 5, r24     

-----------------------------------------------

PORTB = 0; //Turns OFF All LEDs

  80 e0        ldi r24, 0    

  85 b9        out 5, r24  

---------------------------------------------

<__stop_program>:

  ff cf        rjmp .-2 

avr assembler 

http://avra.sourceforge.net/README.html

de terminat 

link to google drive unde am salvat avrdude minimal

contiene avra.exe che compila asm:

https://drive.google.com/open?id=0BzDuTPB5XlKOMm1jM29wUk1EQWc

contiene avra.exe ma anche bin2hex e disavr

https://drive.google.com/open?id=0BzDuTPB5XlKOalVhMkI2VkQzWUE

http://www.atmel.com/images/doc1022.pdf

http://www.alberti-porro.gov.it/wordpress/wp-content/uploads/2014/01/ProgrammareArduino.pdf