__ramfunc void Usart_c_irq_handler(void)
{
	AT91PS_USART USART_pt = AT91C_BASE_US0;
	unsigned int status;
	//* get Usart status register
	status = USART_pt->US_CSR;
	if ( status & AT91C_US_RXRDY){
		//* Get byte and send
		AT91F_US_PutChar (USART_pt, AT91F_US_GetChar(USART_pt));
	}

	if ( status & AT91C_US_OVRE) {
		//* clear US_RXRDY
		 AT91F_US_GetChar(USART_pt);
		 AT91F_US_PutChar (USART_pt, 'O');
	}

	//* Check error
	if ( status & AT91C_US_PARE) {
		 AT91F_US_PutChar (USART_pt, 'P');
	}

	if ( status & AT91C_US_FRAME) {
		 AT91F_US_PutChar (USART_pt, 'F');
	}

	if ( status & AT91C_US_TIMEOUT){
		USART_pt->US_CR = AT91C_US_STTTO;
		 AT91F_US_PutChar (USART_pt, 'T');
	}

	//* Reset the satus bit
	 USART_pt->US_CR = AT91C_US_RSTSTA;
}