UART0 to UART2 gateway (sort of) for AtMega2560 - interrupt

Question

I connected a device to the UART0 of the AtMega2560. I want to transfer the UART0 data to the UART2 to view it on the Terminal(PC).
When I connect the device directly to the PC using an UART to serial device (FTDI) It sends the data nicely.
When I put the UART2 in the middle for said purpose, then It only sends the first line, specifically:
Ver V2DAPV142 On-Line: And then forgets. Sometimes it doesn't send the first line too.
Code:
#define UART0_BUFFER_SIZE 40
#define RX_WAIT 65000
volatile unsigned char UART0_rx_ArrUC85[UART0_BUFFER_SIZE];
volatile unsigned char UART0_rx_ArrLength = 0, UART0_rx_ArrIndex = 0;
void uart0_init( unsigned int baudrate )
{
UBRR0H = (unsigned char) (baudrate>>8);
UBRR0L = (unsigned char) baudrate;
UCSR0B = ( 1 << RXEN0 ) | ( 1 << TXEN0 ) | (1<<RXCIE0);
UCSR0C = ( 1 << USBS0 ) | ( 1 << UCSZ01 ) | ( 1 << UCSZ00 ); // 8N1
}
void USART2Init(UINT16 ubrr_value)
{
UBRR2L = ubrr_value;
UBRR2H = (ubrr_value>>8);
UCSR2C|=(3<<UCSZ20);
UCSR2B = (1<<RXEN2) | (1<<TXEN2);
}
ISR(USART0_RX_vect)
{
unsigned char recChar = UDR0;
if (UART0_BUFFER_SIZE > UART0_rx_ArrLength)
{
UART0_rx_ArrUC85[UART0_rx_ArrIndex++] = recChar;
UART0_rx_ArrLength = UART0_rx_ArrIndex;
}
}
void uart2_putchar(UINT8 data)
{
//Local variables
unsigned int i;
for( i = 0; !( UCSR2A & ( 1 << UDRE2 ) ); i++ ) // Wait for empty transmit buffer
{
if( i > RX_WAIT ) // How long one should wait
{
return ; // Give feedback to function caller
}
}
UDR2 = data; // Start transmitting
//return (int)data; // Cast and return int value
}
void uart2_puts(unsigned char *str)
{
UINT8 dat;
for( ;*str != '\0'; )
{
dat= *str++ ;
uart2_putchar(dat);
}
}
int main()
{
USART2Init(8);
uart0_init(103);
sei();
while(1)
{
if(UART0_rx_ArrLength>0)
{
uart2_puts((unsigned char *) UART0_rx_ArrUC85);
UART0_rx_ArrLength = UART0_rx_ArrIndex = 0;
}
}
}
What could be the issue.
I checked it with same and different baud rates too for UART0 and UART2.

Answer 1

The issue was circuitry power level. The power supply was not sufficient for the Pen-Drive ctrlr and the regulator was not able to source for its communication power level. Hence it was not working sometimes. Further we have tested it and drew a conclusion that after giving sufficient power to the Pen-Drive ctrlr using another power regulator, the above said communication takes nicely place. I hope this can help ppl to draw attention towards the possible circuitry issues.