I keep receiving 0 in the output no matter what I send - c

Question

I am working on a project where I have to establish a communication between my microprocessor and a Bluetooth device. I established a communication, but no matter what I send, I only get 0 when I print it. Thanks for the help !
#include <asf.h>
#include <string.h>
#include <stdio.h>
#include "usart.h"
/**
* Configure serial console.
*/
static void configure_console(void)
{
const usart_serial_options_t uart_serial_options = {
.baudrate = CONF_UART_BAUDRATE,
#ifdef CONF_UART_CHAR_LENGTH
.charlength = CONF_UART_CHAR_LENGTH,
#endif
.paritytype = CONF_UART_PARITY,
#ifdef CONF_UART_STOP_BITS
.stopbits = CONF_UART_STOP_BITS,
#endif
};
/* Configure console. */
stdio_serial_init(CONF_UART, &uart_serial_options);
}
volatile uint32_t ul_ms_ticks = 0;
static void mdelay(uint32_t ul_dly_ticks)
{
uint32_t ul_cur_ticks;
ul_cur_ticks = ul_ms_ticks;
while ((ul_ms_ticks - ul_cur_ticks) < ul_dly_ticks) {
}
}
void SysTick_Handler(void)
{
ul_ms_ticks++;
}
#define USART_SERIAL USART1
#define USART_SERIAL_ID ID_USART1 //USART1 for sam4l
#define USART_SERIAL_BAUDRATE 9600
#define USART_SERIAL_CHAR_LENGTH US_MR_CHRL_8_BIT
#define USART_SERIAL_PARITY US_MR_PAR_NO
#define USART_SERIAL_STOP_BIT US_MR_NBSTOP_1
int main(void)
{
/* Initialize the SAM system */
sysclk_init();
board_init();
/* Initialize the console uart */
configure_console();
uint32_t a= 1234;
int bit_rx = 6;
if (SysTick_Config(sysclk_get_cpu_hz() / 1000)) {
while (1) { /* Capture error */
}
}
const sam_usart_opt_t usart_console_settings = {
USART_SERIAL_BAUDRATE,
USART_SERIAL_CHAR_LENGTH,
USART_SERIAL_PARITY,
USART_SERIAL_STOP_BIT,
US_MR_CHMODE_NORMAL
};
#if SAM4L
sysclk_enable_peripheral_clock(USART_SERIAL);
#else
sysclk_enable_peripheral_clock(USART_SERIAL_ID);
#endif
usart_enable_tx(USART_SERIAL);
usart_enable_rx(USART_SERIAL);
while (1) {
printf("%d \n", bit_rx );
usart_getchar(USART_SERIAL, &a);
bit_rx = a;
printf("%d \n",bit_rx );
if (a != 0) {
ioport_set_pin_level(LED_0_PIN, LED_0_ACTIVE);
} else {
ioport_set_pin_level(LED_0_PIN, !LED_0_ACTIVE);
}
}
}

Answer 1

Perhaps you shouldn't call usart_getchar() until usart_is_rx_ready() returns 1.

Answer 2

Thanks everyone !
I tried to cast the received variable first : bit_rx = (int) a;
And then I found that I needed this to make it work :
static usart_serial_options_t usart_options = {
.baudrate = USART_SERIAL_BAUDRATE,
.charlength = USART_SERIAL_CHAR_LENGTH,
.paritytype = USART_SERIAL_PARITY,
.stopbits = USART_SERIAL_STOP_BIT
};
usart_serial_init(USART_SERIAL, &usart_options);
And I disabled the stop bit, because my bluetooth didn't have one :
#define USART_SERIAL_STOP_BIT false
Now it works like a charm. Thanks all for your help !