SPI Basic polling of EFM32 on-chip peripheral--usart

Configure the Usart module as the most basic SPI mode. No interruption, dead loop sent.

Example:

#include <stdint.h>
#include <stdbool.h>
#include "Efm32.h"
#include "Efm32_chip.h"
#include "Efm32_cmu.h"
#include "efm32_gpio.h"
#include "Efm32_usart.h"

void spi_initial (void)
{
    cmu_clockenable (Cmuclock_hfper, true);
    Cmu_clockenable (Cmuclock_gpio, true);
    cmu_clockenable (Cmuclock_usart1, true);
   
    usart_initsync_typedef spi_init = usart_initsync_default;
 & nbsp;  spi_init.baudrate = 200000;
   
    usart_initsync (USART1, &spi_init);
   
    Gpio_pinmodeset (gpioportd,0,gpiomodepushpull,1); TX
    Gpio_pinmodeset (gpioportd,1,gpiomodeinput,1);   //rx
     Gpio_pinmodeset (gpioportd,2,gpiomodepushpull,1); CLK
    Gpio_pinmodeset (gpioportd,3,gpiomodepushpull,1);//cs
   
    Usart1->route |= Usart_route_cspen | Usart_route_clkpen | Usart_route_txpen | Usart_route_rxpen | Usart_route_location_loc1;
}

/**************************************************************************//**
* @brief Main function
*****************************************************************************/
/**************************************************************************//**
* @brief Main function
*****************************************************************************/
int main (void)
{
/* Chip Errata */
Chip_init ();
Systemcoreclockupdate ();

Spi_initial ();

/* Infinite Blink loop */
while (1)
{
unsigned long uldelay = 4000;
while (uldelay--);
Usart_tx (usart1,0x55);
}
}