DS2401 is a 64-bit ROM memory that used as a hardware-serial-number. [Datasheet : here] It has only two pin. One of them is ground and one of them is Data/Power pin. So for communicate with this chip there is a protocol that called 1-Wire. [1-Wire tutorial : here and here . ]
I want to read my DS2401 chip with AVR ATmega32 , and I use 1wire.h library in codevision. As mentioned in Codevision AVR User Manual [Here] I must use w1_read() function to read a byte of DS2401. but it returns me only 255 [On the LCD]!
This is my codevision code:
/***************************************************** This program was produced by the CodeWizardAVR V2.05.0 Professional Automatic Program Generator © Copyright 1998-2010 Pavel Haiduc, HP InfoTech s.r.l. http://www.hpinfotech.com Project : Version : Date : 7/19/2014 Author : Company : Comments: Chip type : ATmega32A Program type : Application AVR Core Clock frequency: 1.000000 MHz Memory model : Small External RAM size : 0 Data Stack size : 512 *****************************************************/ #include <mega32a.h> #include <delay.h> #include <stdio.h> // 1 Wire Bus interface functions #include <1wire.h> // Alphanumeric LCD Module functions #include <alcd.h> // Declare your global variables here void main(void) { int init_res,read_byte,i; char read_byte_char[64]; // Declare your local variables here // Input/Output Ports initialization // Port A initialization // Func7=In Func6=In Func5=In Func4=In Func3=In Func2=In Func1=In Func0=In // State7=T State6=T State5=T State4=T State3=T State2=T State1=T State0=T PORTA=0x00; DDRA=0x00; // Port B initialization // Func7=In Func6=In Func5=In Func4=In Func3=In Func2=In Func1=In Func0=In // State7=T State6=T State5=T State4=T State3=T State2=T State1=T State0=T PORTB=0x00; DDRB=0x00; // Port C initialization // Func7=In Func6=In Func5=In Func4=In Func3=In Func2=In Func1=In Func0=In // State7=T State6=T State5=T State4=T State3=T State2=T State1=T State0=T PORTC=0x00; DDRC=0x00; // Port D initialization // Func7=In Func6=In Func5=In Func4=In Func3=In Func2=In Func1=In Func0=In // State7=T State6=T State5=T State4=T State3=T State2=T State1=T State0=T PORTD=0x00; DDRD=0x00; // Timer/Counter 0 initialization // Clock source: System Clock // Clock value: Timer 0 Stopped // Mode: Normal top=0xFF // OC0 output: Disconnected TCCR0=0x00; TCNT0=0x00; OCR0=0x00; // Timer/Counter 1 initialization // Clock source: System Clock // Clock value: Timer1 Stopped // Mode: Normal top=0xFFFF // OC1A output: Discon. // OC1B output: Discon. // Noise Canceler: Off // Input Capture on Falling Edge // Timer1 Overflow Interrupt: Off // Input Capture Interrupt: Off // Compare A Match Interrupt: Off // Compare B Match Interrupt: Off TCCR1A=0x00; TCCR1B=0x00; TCNT1H=0x00; TCNT1L=0x00; ICR1H=0x00; ICR1L=0x00; OCR1AH=0x00; OCR1AL=0x00; OCR1BH=0x00; OCR1BL=0x00; // Timer/Counter 2 initialization // Clock source: System Clock // Clock value: Timer2 Stopped // Mode: Normal top=0xFF // OC2 output: Disconnected ASSR=0x00; TCCR2=0x00; TCNT2=0x00; OCR2=0x00; // External Interrupt(s) initialization // INT0: Off // INT1: Off // INT2: Off MCUCR=0x00; MCUCSR=0x00; // Timer(s)/Counter(s) Interrupt(s) initialization TIMSK=0x00; // USART initialization // USART disabled UCSRB=0x00; // Analog Comparator initialization // Analog Comparator: Off // Analog Comparator Input Capture by Timer/Counter 1: Off ACSR=0x80; SFIOR=0x00; // ADC initialization // ADC disabled ADCSRA=0x00; // SPI initialization // SPI disabled SPCR=0x00; // TWI initialization // TWI disabled TWCR=0x00; // 1 Wire Bus initialization // 1 Wire Data port: PORTB // 1 Wire Data bit: 2 // Note: 1 Wire port settings must be specified in the // Project|Configure|C Compiler|Libraries|1 Wire IDE menu. // w1_init(); <------------------------- // Alphanumeric LCD initialization // Connections specified in the // Project|Configure|C Compiler|Libraries|Alphanumeric LCD menu: // RS - PORTA Bit 0 // RD - PORTA Bit 1 // EN - PORTA Bit 2 // D4 - PORTA Bit 4 // D5 - PORTA Bit 5 // D6 - PORTA Bit 6 // D7 - PORTA Bit 7 // Characters/line: 16 lcd_init(16); while (1) { init_res = w1_init(); if (init_res ==1) { lcd_clear(); lcd_gotoxy(1,0); lcd_puts("Chip Connected"); delay_ms(1000); lcd_clear(); lcd_gotoxy(1,0); lcd_puts("Serial Number:"); for (i=1;i<9;i++) { read_byte=w1_read(); lcd_gotoxy(i,1); sprintf(read_byte_char,"%i",read_byte); lcd_puts(read_byte_char); delay_ms(1000); }; } else { lcd_clear(); lcd_gotoxy(1,1); lcd_puts("Chip Not Found"); } delay_ms(2000); } } Q1: Why?
Q2: Each time that I call w1_read function, DS2401 send me next 1 byte? or the same first 1 byte? or total of the ROM?
