Minimalist A-go-go

I just added one switch, which changes LED blinking interval by the following source...

.def R_TEMP1	=R17
.def R_TEMP2	=R18
.def R_TEMP3	=R19
.def R_TEMP4	=R20
.def sw_cond	=R21
.equ led_p	= 3
.equ sw_in	= 4
.equ	SUB_COUNT = 8
	RJMP MAIN

MAIN:
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
	LDI R_TEMP1, 4 ; prescaler of timer0 setting
	OUT TCCR0B, R_TEMP1; clock of CPU divided by 5= 1024,4=256,3=64
; real frequency of blink will be (MPU clock)/256/precsaler value
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
	LDI R_TEMP1, 1<<PUD
	OUT MCUCR, R_TEMP1
	LDI R_TEMP1, (1<<led_p) ;seting PORTB for output
	OUT DDRB, R_TEMP1;seting led_p for output
	LDI R_TEMP2, (1<<led_p)|(1<<sw_in);led_p=PB3 on, sw_in=pullup
    OUT PORTB, R_TEMP2

LOOPPOINT:
	SBI PINB, led_p; flip led on and off
	IN R_TEMP3, PINB ; reading state of portb
	ANDI R_TEMP3, (1<<sw_in) ; checking sw status
	BRNE ANOTHER; if sw_in not equal 1, jump to ANOTHER
	LDI sw_cond, 0; putting sw_cond to zero if sw_in is zero
	RJMP POINT
ANOTHER:
	LDI sw_cond, 1; putting sw_cond to 1 if sw_in is one
POINT:
	RCALL DELAY2
	SBI PINB, led_p ; flip led on and off
	RCALL	DELAY2; calling subroutine delay
	RJMP LOOPPOINT ;jump to LOOPPOINT

DELAY2:	; subroutine DELAY
	LDI R_TEMP4, 1
	ANDI sw_cond, 1 ; checking current sw condition
	BRNE COUNTER2 ; if switch is zero, jump to COUNTER2
	LDI R_TEMP4, SUB_COUNT
COUNTER2:
	IN R_TEMP1, TIFR0; loading current state (TIFR0) of TIMER0
	ANDI	R_TEMP1, 1<<TOV0; checking overflow flag TOV0
	BREQ	COUNTER2 ; if counter is not overflow, jump to COUNTER2
	LDI	R_TEMP1, 1<<TOV0 ; writing 1 to TOV0 leads to reset of TIMER0
	OUT	TIFR0, R_TEMP1
	LDI R_TEMP3, 1
	SUB R_TEMP4, R_TEMP3 ; decrease 1 to SUB_COUNT number
	BRNE COUNTER2 ; if count by sub_count is finished, ret,else to counter2
	RET

This source provides 227 bytes .hex file. Still I have much room for programming on ATtiny13..

I've wanted to make "LED blink" by Assembly, C, and Arduino IDE and compare them, and see how they are working. Here is a result.

Firstly I made a simple Assembly code of LED blinking connecting PB0 and PB1 with LEDs in Atmel Studio. As a initial test, I did not use timer and its internal interrupt. Delay function is made by consuming time by 256x256 step empty loop.

.def R_TEMP1	=R17
.def R_TEMP2	=R18
.def R_TEMP3	=R19
.def R_TEMP4	=R20

.equ	COUNT_START	= 0xFF;256
.equ	COUNT_END	= 0x01; counter end in delay loop
.equ	SUB_COUNT	= 0xFF;256
.equ	SUBNUM	=	0x01; subtract number in delay roop
.org 0x0010
	RJMP MAIN

MAIN:
	LDI R_TEMP1, 0B11111111 ;seting PORTB for output
	OUT DDRB, R_TEMP1;seting PORTB for output
	LDI R_TEMP2, 0B00001000 ;PB3=1(ON), rest are 0(OFF)
    OUT PORTB, R_TEMP2;PB3=1(ON), rest are 0(OFF)

LOOPPOINT:

	LDI R_TEMP2, 0B00001000
    OUT PORTB, R_TEMP2 ; setting PB3=1 (ON)
	RCALL	DELAY; calling subroutine delay
	LDI R_TEMP2, 0B00010000; setting PB4=1 (ON), rest are off
    OUT PORTB, R_TEMP2; setting PB4=1 (ON), rest are off
	RCALL	DELAY; calling subroutine delay
	RJMP LOOPPOINT ;jump to LOOPPOINT

DELAY:	; subroutine DELAY
	LDI	R_TEMP4, SUB_COUNT
SUB_COUNT1:
	LDI	R_TEMP3, COUNT_END
	LDI	R_TEMP1, COUNT_START
	LDI	R_TEMP2, SUBNUM
COUNTER:
	SUB	R_TEMP1, R_TEMP2
	CPSE	R_TEMP1, R_TEMP3
	RJMP COUNTER	
	SUB	R_TEMP4, R_TEMP2
	CPSE	R_TEMP4,	R_TEMP3
	RJMP	SUB_COUNT1
	RET	

This leads to 161 bytes .hex file.

Let's see next, by C by Atmel Studio C,

#include <avr/io.h>
#include <stdlib.h>
#include <util/delay.h>

int main(void)
{
	unsigned int delay = 100;

	// Set up Port B pin 3 and 4 mode to output
	DDRB = 0b00011000;

	// Set up Port B for initial state (PB4=1, rest are 0)
	PORTB = 0b00010000;

	while (1) {
		// Toggle Port B pin 3 and 4
		PORTB ^= 1<<PB4;
		PORTB ^= 1<<PB3;
		// delay of delay ms
		_delay_ms (delay);
	}
}

Now let's see the case of Arduino..

void setup() {
  pinMode(3, OUTPUT);
  pinMode(4, OUTPUT);
}
void loop() {
  digitalWrite(3, LOW);   
  digitalWrite(4, HIGH);   
  delay(1000);             
  digitalWrite(3, HIGH);   
  digitalWrite(4, LOW);   
  delay(1000);              
}

I will go forward, step by step.... stay tune!