STM32F103C8T6 7-segment LED ve UART kullanımı

#include <libopencm3/stm32/rcc.h>
#include <libopencm3/stm32/gpio.h>
#include <libopencm3/stm32/usart.h>
#include <libopencm3/stm32/spi.h>
#include <stdio.h>
#include <string.h>

static void clock_setup(void)
{
        rcc_clock_setup_pll(&rcc_hse_configs[RCC_CLOCK_HSE8_72MHZ]);
}



static void
uart_setup(void) {

                rcc_periph_clock_enable(RCC_GPIOA);
                rcc_periph_clock_enable(RCC_GPIOB);
        rcc_periph_clock_enable(RCC_USART1);
       gpio_set_mode(GPIOA,
                GPIO_MODE_OUTPUT_50_MHZ,
                GPIO_CNF_OUTPUT_ALTFN_PUSHPULL,
                GPIO_USART1_TX);
        usart_set_baudrate(USART1,115200);
        usart_set_databits(USART1,8);
        usart_set_stopbits(USART1,USART_STOPBITS_1);
        usart_set_mode(USART1,USART_MODE_TX_RX);
        usart_set_parity(USART1,USART_PARITY_NONE);
        usart_set_flow_control(USART1,USART_FLOWCONTROL_NONE);
        usart_enable(USART1);
}

static void spi_setup(void) {
        rcc_periph_clock_enable(RCC_SPI1);
        //gpio_set_mode(GPIOB, GPIO_MODE_OUTPUT_50_MHZ, GPIO_CNF_OUTPUT_ALTFN_PUSHPULL, GPIO3| GPIO4 | GPIO5);

        gpio_set_mode(GPIOA, GPIO_MODE_OUTPUT_50_MHZ, GPIO_CNF_OUTPUT_ALTFN_PUSHPULL, GPIO7 | GPIO6 | GPIO5);
        // gpio_set_mode(GPIOA, GPIO_MODE_OUTPUT_50_MHZ, GPIO_CNF_OUTPUT_PUSHPULL, GPIO7 | GPIO6 | GPIO5);

        spi_reset(SPI1);
        spi_init_master(SPI1, SPI_CR1_BAUDRATE_FPCLK_DIV_4, SPI_CR1_CPOL_CLK_TO_0_WHEN_IDLE,
                SPI_CR1_CPHA_CLK_TRANSITION_1, SPI_CR1_DFF_8BIT, SPI_CR1_MSBFIRST);
        // spi_set_nss_high(SPI1);
        spi_set_baudrate_prescaler(SPI1, 4);
        spi_enable(SPI1);
}

int main(void)
{
        clock_setup();
        uart_setup();
        spi_setup();
        while(1) {
        gpio_clear(GPIOA, GPIO6);
        spi_send(SPI1, 17);
        for(int i=0;i<1000*1000*10;i++) {}
        gpio_set(GPIOA, GPIO6); // SHCP

        }
        return 0;
}