Ложные срабатывания прерываний uart?

void uart_sc_mode(void) {
	LPC_SYSCON->SYSAHBCLKCTRL |= (1 << 12);
	LPC_SYSCON->UARTCLKDIV &= ~0xff;
	LPC_SYSCON->UARTCLKDIV |= 0x01;
	
	LPC_IOCON->PIO0_19 &= ~(0x7f 			// clear 0-6 bits
										| (1 << 10));		// clear 10 bit
	LPC_IOCON->PIO0_19 |= (1 << 0)		// TXD mode
										| (1 << 10);		// Open-drain mode
	
/*	LPC_IOCON->PIO0_18 &= ~(0x7f			// clear 0-6 bits
										| (1 << 10));   // clear 10 bit
	LPC_IOCON->PIO0_18 |= (1 << 0) 		// RXD mode
										| (1 << 10);		// Open-drain mode*/
	
	LPC_IOCON->PIO0_17 &= ~(0x7f			// clear 0-6 bits
										| (1 << 10));		// clear 10 bit
	LPC_IOCON->PIO0_17 |= 0x03;       // SCLK mode
	
	LPC_USART->SCICTRL |= 0x01;				// Asynchronous half-duplex sc interface enable
	LPC_USART->SCICTRL &= ~(3 << 1);	// A NACK response is inhibited; T = 0
	
	uart_sc_mode_config(SystemFrequency, 3570000, 372);
	
	LPC_USART->IER = IER_RBR | IER_RLS;
							
}

void uart_sc_mode_config(uint32_t sys_clk, uint32_t Freq, uint32_t scale) {
	uint32_t divider = ( ( ( sys_clk * 2 ) / Freq ) + 1 ) >> 1;
	
	NVIC_DisableIRQ(UART_IRQn);
	
	LPC_USART->LCR &= ~0x9f;
	LPC_USART->LCR |= ( 3 << 0 )	// 8 bit
								| ( 0 << 2 )		// 1 stop bit
								| ( 1 << 3 )		// parity enable
								| ( 1 << 4 )		// even parity
								| ( 1 << 7 ); 	// DLAB = 1
	
	LPC_USART->DLL &= ~0xff;
	LPC_USART->DLM &= ~0xff;
	
	LPC_USART->DLM = ( divider >> 8 ) & 0xff;	
	LPC_USART->DLL = divider & 0xff;
		
	LPC_USART->LCR &= ~( 1 << 7 );	// DLAB = 0
	
	LPC_USART->FCR |= ( 1 << 0 ) 	// enable access to the other field in register
								| ( 1 << 1 )		// enable and clear RxBuff
								| ( 1 << 2 )		// enable and clear TxBuff
								| ( 0 << 6 ); 	// interrupt after every recieve byte
	
	LPC_USART->OSR &= ~( 0x3fff );
	LPC_USART->OSR = ( scale - 1 ) << 4;
	
	LPC_USART->SCICTRL &= ~( ( 0xff << 8 ) | ( 0x07 << 5 ) );
	LPC_USART->SCICTRL |= ( 0xff << 8 ) | ( 0x07 << 5 );
	
	NVIC_EnableIRQ(UART_IRQn);
} 

void 
UART_IRQHandler( void ) 
{
	timer0_stop();
	timer0_reset();
	if ( ( LPC_USART->IIR >> 1 ) & IIR_RDA )	{
		g_UartMsg.buffer[g_UartMsg.byteCount++] = LPC_USART->RBR;
	}
	timer0_start(TIMEOUT_DEFAULT_BYTE, g_etu2ticks);
}