Why can't I put command in ATMEGA64A-AU serial?

Question

I've bought an ATMEGA64A-AU and I connected its USART0 to FT232RL(USB to serial) and its USART1 to GSM module.

I use USART0 for monitoring only purpose and USART1 to communicate with GSM module.

I wrote these to enable USARTs:

void USART0_Init( unsigned int ubrr )
{
    UBRR0H = (unsigned char) (ubrr >> 8);
    UBRR0L = (unsigned char) ubrr;
    UCSR0B = (1 << RXEN0) | (1 << TXEN0) | (1 << RXCIE0);
    UCSR0C = (1 << USBS0) | (3 << UCSZ00);
}

void USART1_Init( unsigned int ubrr )
{
    UBRR1H = (unsigned char) (ubrr >> 8);
    UBRR1L = (unsigned char) ubrr;
    UCSR1B = (1 << RXEN1) | (1 << TXEN1) | (1 << RXCIE1);
    UCSR1C = (1 << USBS1) | (3 << UCSZ01);
}

And these to put char or string in each USART:

void usart0_putc (char send)
{
    while ((UCSR0A & (1 << UDRE0)) == 0) {};
    UDR0 = send;
}

void usart0_puts (const char *send)
{
    while (*send) {
        usart0_putc(*send++);
    }
}

void usart1_putc (char send)
{
    while ((UCSR1A & (1 << UDRE1)) == 0) {};
    UDR1 = send;
}

void usart1_puts (const char *send)
{
    while (*send) {
        usart1_putc(*send++);
    }
}

I used RX1 interrupt vector to get response from module:

ISR (USART1_RX_vect)
{
    data_in[data_count] = UDR1;
    if (data_in[data_count] == '\n') {
        command_ready = TRUE;
        data_count = 0;
    } else {
        data_count++;
    }

}

And the main function:

void main( void )
{
    sei();
    
    USART0_Init(MYUBRR);
    USART1_Init(MYUBRR);
    while(1){
        if (command_ready == TRUE) {
            memcpy(command_in, data_in, MAXCHAR );
            memset(data_in, 0, sizeof(data_in));
            usart0_puts(command_in);
            command_ready = FALSE;
        }
        
    }
}

It shows the response or anything like ringing and messages but the problem is , when I put some command to it by micro controller like putting this line before main while loop :

usart1_puts("ATD+545555555555;\r\n");

To call some number, the whole thing stops and not only it don't call that number but it stops showing responses from module, so I thought there is something wrong with the code.

Any help would be appreciated.

Answer 1

You have to change the line :

UCSR1C = (1 << USBS1) | (3 << UCSZ01);

to this : UCSR1C = (1 << USBS1) | (3 << UCSZ10);

UCSZ01 bit belongs to USART0 not USART1 according to the datasheet!

Answer 2

You have the Receive Completed Interrupt (RXCIE0) Enabled in UCSR0B

 UCSR0B = (1 << RXEN0) | (1 << TXEN0) | (1 << RXCIE0);

but you have no Interrupt Service Routine handler for that interrupt vector.

All vectors with undeclared interrupt handlers default to infinite loop, which hang the program.

You have to either declare ISR (USART0_RX_vect) or remove RXCIE0 from UCSR0B