Echo with USART1 on STM32L-Discovery

STM32L_USART1.c

#include "stm32l1xx.h"

int main(void)
{
	RCC->CR |= RCC_CR_HSEON;
	while(!(RCC->CR & RCC_CR_HSERDY));

	RCC->APB2ENR	|= RCC_APB2ENR_USART1EN;	//USART1 Clock ON
	USART1->BRR = 0xD05;		// Bodrate for 9600 on 32Mhz
	USART1->CR1  |= USART_CR1_UE | USART_CR1_TE | USART_CR1_RE; // USART1 ON, TX ON, RX ON

	RCC->AHBENR |= RCC_AHBENR_GPIOAEN | RCC_AHBLPENR_GPIOALPEN;
	GPIOA->AFR[1] |= 0x770; //AF7(USART1..3) to pins 9,10

	GPIOA->OTYPER &= ~GPIO_OTYPER_ODR_9; // Output push-pull (reset state)
	GPIOA->PUPDR &= ~GPIO_PUPDR_PUPDR9; // No pull-up, pull-down
	GPIOA->MODER |= GPIO_MODER_MODER9_1; // Alternate function mode
	GPIOA->OSPEEDR |= GPIO_OSPEEDER_OSPEEDR9_1; // 40 MHz High speed

	GPIOA->MODER |= GPIO_MODER_MODER10_1; // Alternate function mode
	GPIOA->OSPEEDR |= GPIO_OSPEEDER_OSPEEDR10_1; // 40 MHz High speed


	USART1->CR1 |= USART_CR1_RXNEIE; // RXNE Int ON
	NVIC_EnableIRQ (USART1_IRQn);
	__enable_irq ();

	while (1) {
	}
}

void USART1_IRQHandler(void) {
	if (USART1->SR & USART_SR_RXNE) {
		while(!(USART1->SR & USART_SR_TC));
		USART1->DR = USART1->DR;
	}
}