mandriva
Newbie level 4
Hi My Dear Friends,
I want to store an string on a location of FM24C256 FRAM and then retrieve it and display on a alphanumeric LCD. As this memory uses I2C, I have used CodevisionAVR's I2C example to implement my project. The problem is that it seems write operation is done correctly (I am not completely sure) but when I read the memory starting from the same location as write starting location, I get LCD full of unknown character. I have attached my code and circuit's schematic.
Any helpful idea will get rewards in paradise.
[/quote]
I want to store an string on a location of FM24C256 FRAM and then retrieve it and display on a alphanumeric LCD. As this memory uses I2C, I have used CodevisionAVR's I2C example to implement my project. The problem is that it seems write operation is done correctly (I am not completely sure) but when I read the memory starting from the same location as write starting location, I get LCD full of unknown character. I have attached my code and circuit's schematic.
Any helpful idea will get rewards in paradise.
#include <mega32.h>
#include <stdio.h>
// I2C Bus functions
#asm
.equ __i2c_port=0x1B ;PORTA
.equ __sda_bit=0
.equ __scl_bit=1
#endasm
#include <i2c.h>
// Alphanumeric LCD Module functions
#asm
.equ __lcd_port=0x15 ;PORTC
#endasm
#include <lcd.h>
#include <delay.h>
#define BUS_ADDRESS 0xa0
unsigned char read_fram(unsigned int address)
{
unsigned char data;
i2c_start();
i2c_write(BUS_ADDRESS);
i2c_write(address);
i2c_start();
i2c_write(BUS_ADDRESS | 1);
data = i2c_read(1);
i2c_stop();
return data;
}
void write_fram(unsigned int address, unsigned char data)
{
i2c_start();
i2c_write(BUS_ADDRESS);
i2c_write(address);
i2c_write(data);
i2c_stop();
delay_ms(20);
}
char* fram_gets(unsigned int start_addr)
{
char *t;
char c;
char str[33];
char i = 0;
lcd_clear();
while ((c = read_fram(start_addr)) != '\n')
{
sprintf(t, "%c", c);
lcd_puts(t);
str[i++] = c;
start_addr++;
}
str = '\n';
return(str);
}
void fram_puts(unsigned int start_addr, char str[])
{
char i = 0;
while (str != '\n')
{
write_fram(start_addr, str);
start_addr++;
i++;
}
}
void main(void)
{
// Declare your local variables here
char *str = "I2C";
// 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=0xFF;
// 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=FFh
// OC0 output: Disconnected
TCCR0=0x00;
TCNT0=0x00;
OCR0=0x00;
// Timer/Counter 1 initialization
// Clock source: System Clock
// Clock value: Timer 1 Stopped
// Mode: Normal top=FFFFh
// OC1A output: Discon.
// OC1B output: Discon.
// Noise Canceler: Off
// Input Capture on Falling Edge
// Timer 1 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: Timer 2 Stopped
// Mode: Normal top=FFh
// 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;
// Analog Comparator initialization
// Analog Comparator: Off
// Analog Comparator Input Capture by Timer/Counter 1: Off
ACSR=0x80;
SFIOR=0x00;
// I2C Bus initialization
i2c_init();
// LCD module initialization
lcd_init(16);
lcd_puts(str);
while (1)
{
sprintf(str, "Writing to FRAM.");
lcd_clear();
lcd_puts(str);
delay_ms(1000);
sprintf(str, "This is FRAM test.\n");
fram_puts(0, str);
sprintf(str, "Reading from FRAM.");
lcd_clear();
lcd_puts(str);
delay_ms(1000);
str = fram_gets(0);
lcd_clear();
//lcd_puts(str);
delay_ms(1000);
};
}
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