Configuring UART in STM32F429I DISC1 board

/* p4_5.c C library Console I/O using USART2 at 9600 Baud
 *
 * This program demonstrates the use of C library console I/O.
 * The functions fputc() and fgetc() are implemented using
 * USART2_write() and USART2_read() for character I/O.
 * In the fgetc(), the received character is echoed and if a '\r'
 * is received, a pair of '\r', '\n' is echoed.
 * In fputc() and fgetc(), the file descripter is not checked. All
 * file I/O's are directed to the console.
 *
 * By default, the clock is running at 16 MHz.
 * The USART is configured for 9600 Baud.
 * PA2 - USART2 TX (AF7)
 * PA3 - USART2 RX (AF7)
 * Use Tera Term on the host PC to send keystrokes and observe the display
 * of the characters echoed.
 *
 * This program was tested with Keil uVision v5.24a with DFP v2.11.0
 */
#include "stm32F4xx.h"
#include <stdio.h>
 
void USART2_init(void);
void delayMs(int);
void USART2_write(int c);
int USART2_read(void);
 
int main(void) {
    int n;
    char str[80];
 
    USART2_init();
	  USART2_write('c');
 
    while (1) {
        
    }
}
 
/* initialize USART2 to transmit at 9600 Baud */
void USART2_init (void) {
    RCC->AHB1ENR |= 1;          /* Enable GPIOA clock */
    RCC->APB1ENR |= 0x20000;    /* Enable USART2 clock */
 
    /* Configure PA2, PA3 for USART2 TX, RX */
    GPIOA->AFR[0] &= ~0xFF00;
    GPIOA->AFR[0] |=  0x7700;   /* alt7 for USART2 */
    GPIOA->MODER  &= ~0x00F0;
    GPIOA->MODER  |=  0x00A0;   /* enable alt. function for PA2, PA3 */
 
    USART2->BRR = 0x0683;       /* 9600 baud @ 16 MHz */
    USART2->CR1 = 0x000C;       /* enable Tx, Rx, 8-bit data */
    USART2->CR2 = 0x0000;       /* 1 stop bit */
    USART2->CR3 = 0x0000;       /* no flow control */
    USART2->CR1 |= 0x2000;      /* enable USART2 */
}
 
/* Write a character to USART2 */
void USART2_write (int ch) {
    while (!(USART2->SR & 0x0080)) {}   // wait until Tx buffer empty
    USART2->DR = (ch & 0xFF);
    //return ch;
}
 
/* Read a character from USART2 */
int USART2_read(void) {
    while (!(USART2->SR & 0x0020)) {}   // wait until char arrives
    return USART2->DR;
}