int main(void)
{
unsigned char write_data=0x75, recv_data;
int testn=0;
USART_init();
print_UART(" This is the test for TWI ");
_delay_ms(1000);
PORTD |= 0x80; ///turn led on
_delay_ms(100);
TWI_init_master();
sei();
print_UART(" Sending Start condition ");
TWI_start();
print_UART(" address= %x ", ((address<<1)|write));
TWI_write_address((address<<1)|write);
print_UART(" writing register = %x ", write_data);
TWI_write_byte(write_data); //write register
print_UART(" Repeat Start ");
TWI_start(); //repeated start
print_UART(" address read= %x ", ((address<<1)|read));
TWI_write_address((address<<1)|read);
print_UART(" read Data ");
recv_data=TWI_read_byte(1); ///read byte and nack
TWI_stop();
print_UART(" This is the value of the register= %x ", recv_data);
PORTD &= 0x7F;
return 0;
}
void TWI_ScrollFrame(void)
{
uint8_t segindex=0,i,j;
uint8_t str_Ptr[8];
uint8_t activeStatus = 1;
while((segindex<8) && (NewMsgReceived==0))
{
activeStatus = 1;
NumberOfSegments = 1;
for(i=0; (activeStatus) && (NewMsgReceived==0);i++)
{
for(j=0;j<MaxColPerSegment;j++)
{
str_Ptr[j] = FrameBuffer[(i*8)+j+segindex];
}
if(i==0)
{
for(j=0;j<MaxColPerSegment;j++)
{
pattern[j] = str_Ptr[j];
}
}
else
{
activeStatus = TWI_start(); // Function to send start condition
if(activeStatus)
{
activeStatus = TWI_write_address(i*2+0x30); // Function to write address and data direction bit(write) on SDA
if(activeStatus)
{
NumberOfSegments++;
for(j=0;j<8;j++)
{
TWI_write_data(str_Ptr[j]); // Function to write data in slave
}
}
}
TWI_stop(); // Function to send stop condition
}
}
for(i=NumberOfSegments;i<MAX_DEVICES;i++)
DELAY_ms(SCROLL_DELAY_MS);
segindex++;
}
}
void DisplayString(char *ptr_msgPointer)
{
int i,j;
uint8_t activeStatus = 1;
NumberOfSegments = 1;
BuildFrame(ptr_msgPointer);
for(i=0;activeStatus;i++)
{
if(i==0)
{
for(j=0;j<8;j++)
pattern[j] = FrameBuffer[j];
}
else
{
TWI_start(); // Function to send start condition
activeStatus = TWI_write_address(i*2+0x30); // Function to write address and data direction bit(write) on SDA
if(activeStatus)
{
NumberOfSegments++;
for(j=0;j<8;j++)
{
TWI_write_data(FrameBuffer[i*8+j]); // Function to write data in slave
// UART_TxChar(' ');
// UART_TxHexNumber(i,2); // Function to write data in slave
}
}
TWI_stop(); // Function to send stop condition
}
}
}
int main(void)
{
_delay_ms(2000);
DDRB=0xff;
TWI_init_master(); // Function to initialize TWI
while(1)
{
if(write_data==0x00)
write_data=1;
TWI_start(); // Function to send start condition
TWI_write_address(address+write); // Function to write address and data direction bit(write) on SDA
TWI_write_data(255); // Function to write data in slave
TWI_stop(); // Function to send stop condition
_delay_ms(100); // Delay of 10 mili second
PORTB=0xff;
TWI_start();
TWI_read_address(address+read); // Function to write address and data direction bit(read) on SDA
TWI_read_data(); // Function to read data from slave
TWI_stop();
_delay_ms(2000);
}
}
/////////////////Functions/////////////////////////////////
void TWI_init_master(void) // Function to initialize master
{
TWBR=3; // Bit rate
TWSR=(0<<TWPS1)|(0<<TWPS0); // Setting prescalar bits
PORTD|=(1<<0)|(1<<1);
// SCL freq= F_CPU/(16+2(TWBR).4^TWPS)
TCCR2=0b00001011;
TIMSK|=1<<OCIE2;
OCR2=200;
TWI_start();
TWI_write_address(0xD2);
TWI_write_data(0x20);
TWI_write_data(0b11101111);
TWI_stop();
TWI_start();
TWI_write_address(0xD2);
TWI_write_data(0x23);
TWI_write_data(0b00010000);
TWI_stop();
}
signed short int getdata(unsigned char add)
{
signed short int DATA;
TWI_start();
TWI_write_address(0xD2);
TWI_write_data(add);
TWI_repeated_start();
TWI_read_address(0xD3);
DATA=TWI_read_data();
TWI_stop();
return DATA;
}
